diff --git a/includes/ingest.form.inc b/includes/ingest.form.inc
index 420ebc87..c285c5a1 100644
--- a/includes/ingest.form.inc
+++ b/includes/ingest.form.inc
@@ -12,9 +12,9 @@
  * the current step.
  *
  * @param array $form
- *   The drupal form.
+ *   The Drupal form.
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  * @param array $configuration
  *   An associative array of configuration values that are used to build the
  *   list of steps to be executed, including:
@@ -31,67 +31,196 @@
  *   The form definition of the current step.
  */
 function islandora_ingest_form(array $form, array &$form_state, array $configuration) {
-  islandora_ingest_form_init_form_state($form_state, $configuration);
-  $form = islandora_ingest_form_execute_step($form, $form_state);
-  return $form;
+  islandora_ingest_form_init_form_state_storage($form_state, $configuration);
+  return islandora_ingest_form_execute_step($form, $form_state);
 }
 
 /**
- * Prepares/Initializes the form state for use.
+ * Validates the given ingest configuration.
  *
- * Also cleans up or loads any data required.
+ * At the moment it only requires that models are present.
+ *
+ * @todo Add hook for manipulating/validating the configuration.
+ *
+ * @throws InvalidArgumentException
  *
- * @param array $form_state
- *   The drupal form state.
  * @param array $configuration
- *   A list of key value pairs that are used to build the list of steps to be
- *   executed.
+ *   The key value pairs that are used to build the multi-paged ingest process.
+ *
+ * @see islandora_ingest_form()
+ *
+ * @return bool
+ *   TRUE if the configuration is valid, FALSE otherwise.
  */
-function islandora_ingest_form_init_form_state(array &$form_state, array $configuration) {
-  // First time initialization of storage.
-  islandora_ingest_form_init_form_state_storage($form_state, $configuration);
+function islandora_ingest_form_validiate_configuration(array $configuration) {
+  if (empty($configuration['models'])) {
+    $message = t('Ingest configuration not vaild, no models were given');
+    drupal_set_message($message, 'error');
+    throw new InvalidArgumentException($message);
+  }
 }
 
 /**
  * Initializes the form_state storage for use in the ingest multi-page forms.
  *
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  * @param array $configuration
  *   A list of key value pairs that are used to build the list of steps to be
  *   executed.
  */
 function islandora_ingest_form_init_form_state_storage(array &$form_state, array $configuration) {
   if (empty($form_state['islandora'])) {
-    module_load_include('inc', 'islandora', 'includes/utilities');
-    // Use ID if given.
-    $id = isset($configuration['id']) ? $configuration['id'] : NULL;
-    // Use namespace if ID not given.
-    $namespace = isset($configuration['namespace']) && !isset($id) ? $configuration['namespace'] : $id;
-    $label = isset($configuration['label']) ? $configuration['label'] : 'New Object';
-    $relationship_map = function($o) {
-      return array('relationship' => 'isMemberOfCollection', 'pid' => $o);
-    };
-    $relationships = empty($configuration['collections']) ? array() : array_map($relationship_map, $configuration['collections']);
-    $object = islandora_prepare_new_object($namespace, $label, array(), array(), $relationships);
+    // Validate the configuration before using it.
+    islandora_ingest_form_validiate_configuration($configuration);
+    $object = islandora_ingest_form_prepare_new_object($configuration);
     $form_state['islandora'] = array(
       'step_id' => NULL,
       'objects' => array($object),
-      'configuration' => $configuration,
+      'shared_storage' => $configuration,
       'step_storage' => array(),
     );
   }
+}
+
+/**
+ * Prepares a new object based on the given configuration.
+ *
+ * @param array $configuration
+ *   The list of key/value pairs of configuration.
+ *
+ * @return NewFedoraObject
+ *   The new object.
+ */
+function islandora_ingest_form_prepare_new_object(array $configuration) {
+  module_load_include('inc', 'islandora', 'includes/utilities');
+  // ID is more specific than namespace so it will take precedence.
+  $id = isset($configuration['namespace']) ? $configuration['namespace'] : 'islandora';
+  $id = isset($configuration['id']) ? $configuration['id'] : $id;
+  $label = isset($configuration['label']) ? $configuration['label'] : 'New Object';
+  $relationship_map = function($o) {
+    return array('relationship' => 'isMemberOfCollection', 'pid' => $o);
+  };
+  $relationships = empty($configuration['collections']) ? array() : array_map($relationship_map, $configuration['collections']);
+  return islandora_prepare_new_object($id, $label, array(), array(), $relationships);
+}
+
+/**
+ * Gets the given/current step.
+ *
+ * The current step is returned if no step ID is given. If the current step is
+ * not defined it's assume to be the first step.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ * @param string $step_id
+ *   The ID of the step.
+ *
+ * @return array
+ *   The given/current step if found, NULL otherwise.
+ */
+function islandora_ingest_form_get_step(array &$form_state, $step_id = NULL) {
+  $step_id = isset($step_id) ? $step_id : islandora_ingest_form_get_current_step_id($form_state);
+  $steps = islandora_ingest_form_get_steps($form_state);
+  if (isset($step_id) && isset($steps[$step_id])) {
+    return $steps[$step_id];
+  }
+  return NULL;
+}
 
-  $steps = islandora_ingest_get_steps($form_state);
-  if ($form_state['islandora']['step_id'] === NULL || !array_key_exists(
-    $form_state['islandora']['step_id'], $steps)) {
-    reset($steps);
-    $form_state['islandora']['step_id'] = key($steps);
+/**
+ * Gets the ID of the current step.
+ *
+ * If a current step is not defined, its assumed to be the first step.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
+ * @return string
+ *   The step ID.
+ */
+function islandora_ingest_form_get_current_step_id(array &$form_state) {
+  if (empty($form_state['islandora']['step_id'])) {
+    $steps = islandora_ingest_form_get_steps($form_state);
+    return array_shift(array_keys($steps));
   }
+  return $form_state['islandora']['step_id'];
+}
 
-  // Stash the current configuration in the step.
-  $storage = &islandora_ingest_form_get_step_storage($form_state);
-  $storage['configuration'] = $form_state['islandora']['configuration'];
+/**
+ * Gets the ID of the next step.
+ *
+ * If a current step is not defined, its assumed to be the first step.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
+ * @return string
+ *   The next step ID if found, NULL otherwise.
+ */
+function islandora_ingest_form_get_next_step_id(array &$form_state) {
+  $step_id = islandora_ingest_form_get_current_step_id($form_state);
+  $step_ids = array_keys(islandora_ingest_form_get_steps($form_state));
+  $index = array_search($step_id, $step_ids);
+  $count = count($step_ids);
+  if ($index !== FALSE && ++$index < $count) {
+    return $step_ids[$index];
+  }
+  return NULL;
+}
+
+/**
+ * Gets the ID of the previous step.
+ *
+ * If a current step is not defined, its assumed to be the first step.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
+ * @return string
+ *   The previous step ID if found, NULL otherwise.
+ */
+function islandora_ingest_form_get_previous_step_id(array &$form_state) {
+  $step_id = islandora_ingest_form_get_current_step_id($form_state);
+  $step_ids = array_keys(islandora_ingest_form_get_steps($form_state));
+  $index = array_search($step_id, $step_ids);
+  if ($index !== FALSE && --$index >= 0) {
+    return $step_ids[$index];
+  }
+  return NULL;
+}
+
+/**
+ * Increments the current step if possible.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ */
+function islandora_ingest_form_increment_step(array &$form_state) {
+  // When going to the next step rebuild the list of steps as the submit
+  // of the current step could have added/removed a step.
+  drupal_static_reset('islandora_ingest_form_get_steps');
+  $next_step_id = islandora_ingest_form_get_next_step_id($form_state);
+  if (isset($next_step_id)) {
+    islandora_ingest_form_stash_info($form_state);
+    $form_state['islandora']['step_id'] = $next_step_id;
+    islandora_ingest_form_grab_info($form_state);
+  }
+}
+
+/**
+ * Decrement the current step if possible.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ */
+function islandora_ingest_form_decrement_step(array &$form_state) {
+  $previous_step_id  = islandora_ingest_form_get_previous_step_id($form_state);
+  if (isset($previous_step_id)) {
+    islandora_ingest_form_stash_info($form_state);
+    $form_state['islandora']['step_id'] = $previous_step_id;
+    islandora_ingest_form_grab_info($form_state);
+  }
 }
 
 /**
@@ -106,40 +235,38 @@ function islandora_ingest_form_init_form_state_storage(array &$form_state, array
 function islandora_ingest_get_approximate_steps(array $configuration) {
   $fake_form_state = array(
     'islandora' => array(
-      'configuration' => $configuration,
+      'shared_storage' => $configuration,
     ),
   );
-  $steps = islandora_ingest_get_steps($fake_form_state);
-  drupal_static_reset('islandora_ingest_get_steps');
+  $steps = islandora_ingest_form_get_steps($fake_form_state);
+  drupal_static_reset('islandora_ingest_form_get_steps');
   return $steps;
 }
 
 /**
  * Executes the current step.
  *
- * Builds the form definition and appends any additonal elements required for
- * the step to function.
+ * Builds the form definition and appends on any additonal elements required
+ * for the step to function.
  *
  * @param array $form
- *   The drupal form.
+ *   The Drupal form.
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  *
  * @return array
  *   The form definition of the current step.
  */
 function islandora_ingest_form_execute_step(array $form, array &$form_state) {
   // Load any required files for the current step.
-  islandora_ingest_form_step_form_load_include($form_state);
-
-  $step_info = islandora_ingest_form_get_step_info($form_state);
-
-  switch ($step_info['type']) {
+  islandora_ingest_form_load_include($form_state);
+  $step = islandora_ingest_form_get_step($form_state);
+  switch ($step['type']) {
     case 'form':
       $args = array($form, &$form_state);
-      $args = isset($step_info['args']) ? array_merge($args, $step_info['args']) : $args;
-      $form = call_user_func_array($step_info['form_id'], $args);
-      return islandora_ingest_form_stepify($form, $form_state, $step_info);
+      $args = isset($step['args']) ? array_merge($args, $step['args']) : $args;
+      $form = call_user_func_array($step['form_id'], $args);
+      return islandora_ingest_form_stepify($form, $form_state, $step);
 
     case 'batch':
       // @todo Implement if possible.
@@ -152,37 +279,76 @@ function islandora_ingest_form_execute_step(array $form, array &$form_state) {
  * Append Prev/Next buttons submit/validation handlers etc.
  *
  * @param array $form
- *   The drupal form.
+ *   The Drupal form.
  * @param array $form_state
- *   The drupal form state.
- * @param array $step_info
- *   The info for building the current form step.
+ *   The Drupal form state.
  *
  * @return array
  *   The stepified drupal form definition for the given step.
  */
-function islandora_ingest_form_stepify(array $form, array &$form_state, array $step_info) {
-  $step = islandora_ingest_form_get_step_number($form_state);
-
-  $first_step = $step > 0;
-  $last_step = $step == (islandora_ingest_form_get_step_count($form_state) - 1);
-  $form['prev'] = $first_step ? islandora_ingest_form_previous_button() : NULL;
-  $form['next'] = $last_step ? islandora_ingest_form_ingest_button($step_info) : islandora_ingest_form_next_button($step_info);
+function islandora_ingest_form_stepify(array $form, array &$form_state) {
+  $first_step = islandora_ingest_form_on_first_step($form_state);
+  $last_step = islandora_ingest_form_on_last_step($form_state);
+  $form['prev'] = $first_step ? NULL : islandora_ingest_form_previous_button($form_state);
+  $form['next'] = $last_step ? islandora_ingest_form_ingest_button($form_state) : islandora_ingest_form_next_button($form_state);
   return $form;
 }
 
+/**
+ * Checks if we are on the first step.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
+ * @return bool
+ *   TRUE if we are currently on the first step, FALSE otherwise.
+ */
+function islandora_ingest_form_on_first_step(array &$form_state) {
+  $step_id = islandora_ingest_form_get_current_step_id($form_state);
+  $step_ids = array_keys(islandora_ingest_form_get_steps($form_state));
+  return array_search($step_id, $step_ids) == 0;
+}
+
+/**
+ * Checks if we are on the last step.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
+ * @return bool
+ *   TRUE if we are currently on the last step, FALSE otherwise.
+ */
+function islandora_ingest_form_on_last_step(array &$form_state) {
+  $step_id = islandora_ingest_form_get_current_step_id($form_state);
+  $step_ids = array_keys(islandora_ingest_form_get_steps($form_state));
+  $count = count($step_ids);
+  return array_search($step_id, $step_ids) == --$count;
+}
+
 /**
  * Defines the previous button for the ingest form.
  *
+ * Adds submit handlers for the form step if they exist.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
  * @return array
  *   The previous button for the ingest form.
  */
-function islandora_ingest_form_previous_button() {
+function islandora_ingest_form_previous_button(array &$form_state) {
+  // Before we move back to the previous step we should tell the previous step
+  // to undo whatever its submit handler did.
+  $prev_step_id = islandora_ingest_form_get_previous_step_id($form_state);
+  $prev_step = islandora_ingest_form_get_step($form_state, $prev_step_id);
+  $form_id = $prev_step['form_id'];
+  $submit_callback = $form_id . '_undo_submit';
+  $submit = function_exists($submit_callback) ? array($submit_callback, 'islandora_ingest_form_previous_submit') : array('islandora_ingest_form_undo_submit');
   return array(
     '#type' => 'submit',
     '#value' => t('Previous'),
     '#name' => 'prev',
-    '#submit' => array('islandora_ingest_form_previous_submit'),
+    '#submit' => $submit,
     // #limit_validation_errors, is why when the previous button is pressed no
     // values persisted in the form_state, but its also what allows us to go
     // back when validation errors occur. To have a better solution going
@@ -194,23 +360,6 @@ function islandora_ingest_form_previous_button() {
   );
 }
 
-/**
- * Get the current step.
- *
- * @param array $form_state
- *   The Drupal form state.
- * @param string $step_id
- *   The ID of the step to get.
- */
-function islandora_ingest_form_get_step_number(array $form_state, $step_id = NULL) {
-  if ($step_id === NULL) {
-    $step_id = islandora_ingest_form_get_step_id($form_state);
-  }
-
-  $steps = array_flip(array_keys(islandora_ingest_form_get_steps($form_state)));
-  return $steps[$step_id];
-}
-
 /**
  * The submit handler for the ingest form previous button.
  *
@@ -219,16 +368,12 @@ function islandora_ingest_form_get_step_number(array $form_state, $step_id = NUL
  * Restores the form values for the previous step.
  *
  * @param array $form
- *   The drupal form.
+ *   The Drupal form.
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  */
 function islandora_ingest_form_previous_submit(array $form, array &$form_state) {
-  $step = islandora_ingest_form_get_step_number($form_state);
-  islandora_ingest_form_stash_info($form_state);
-  $step = max(array($step - 1, 0));
-  $form_state['islandora']['step_id'] = islandora_ingest_form_get_step_id($form_state, $step);
-  islandora_ingest_form_grab_info($form_state);
+  islandora_ingest_form_decrement_step($form_state);
   $form_state['rebuild'] = TRUE;
 }
 
@@ -237,11 +382,15 @@ function islandora_ingest_form_previous_submit(array $form, array &$form_state)
  *
  * Adds submit/validate handlers for the form step if they exist.
  *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
  * @return array
  *   The next button for the ingest form.
  */
-function islandora_ingest_form_next_button(array $step_info) {
-  $form_id = $step_info['form_id'];
+function islandora_ingest_form_next_button(array &$form_state) {
+  $step = islandora_ingest_form_get_step($form_state);
+  $form_id = $step['form_id'];
   $validate_callback = $form_id . '_validate';
   $validate = function_exists($validate_callback) ? array($validate_callback) : NULL;
   $submit_callback = $form_id . '_submit';
@@ -263,22 +412,20 @@ function islandora_ingest_form_next_button(array $step_info) {
  * Restores the form values for the next step if present.
  *
  * @param array $form
- *   The drupal form.
+ *   The Drupal form.
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  */
 function islandora_ingest_form_next_submit(array $form, array &$form_state) {
-  $step = islandora_ingest_form_get_step_number($form_state);
-  drupal_static_reset('islandora_ingest_form_get_steps');
-  islandora_ingest_form_stash_info($form_state);
-  $step = min(array($step + 1, islandora_ingest_form_get_step_count($form_state) - 1));
-  $form_state['islandora']['step_id'] = islandora_ingest_form_get_step_id($form_state, $step);
-  islandora_ingest_form_grab_info($form_state);
+  islandora_ingest_form_increment_step($form_state);
   $form_state['rebuild'] = TRUE;
 }
 
 /**
  * Push current info into the current step's storage.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
  */
 function islandora_ingest_form_stash_info(array &$form_state) {
   $storage = &islandora_ingest_form_get_step_storage($form_state);
@@ -288,13 +435,13 @@ function islandora_ingest_form_stash_info(array &$form_state) {
 
 /**
  * Pops the info for the given step from storage into the form_state.
+ *
+ * @param array $form_state
+ *   The Drupal form state.
  */
 function islandora_ingest_form_grab_info(array &$form_state) {
   $storage = islandora_ingest_form_get_step_storage($form_state);
   $form_state['values'] = isset($storage['values']) ? $storage['values'] : array();
-  if (isset($storage['configuration'])) {
-    $form_state['islandora']['configuration'] = $storage['configuration'];
-  }
 }
 
 /**
@@ -302,11 +449,15 @@ function islandora_ingest_form_grab_info(array &$form_state) {
  *
  * This button is only shown on the last page of the multi-page ingest form.
  *
+ * @param array $form_state
+ *   The Drupal form state.
+ *
  * @return array
  *   The ingest button for the ingest form.
  */
-function islandora_ingest_form_ingest_button(array $step_info) {
-  $form_id = $step_info['form_id'];
+function islandora_ingest_form_ingest_button(array &$form_state) {
+  $step = islandora_ingest_form_get_step($form_state);
+  $form_id = $step['form_id'];
   $validate_callback = $form_id . '_validate';
   $validate = function_exists($validate_callback) ? array($validate_callback) : NULL;
   $submit_callback = $form_id . '_submit';
@@ -326,9 +477,9 @@ function islandora_ingest_form_ingest_button(array $step_info) {
  * Attempts to ingest every object built by the previous steps.
  *
  * @param array $form
- *   The drupal form.
+ *   The Drupal form.
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  */
 function islandora_ingest_form_submit(array $form, array &$form_state) {
   foreach ($form_state['islandora']['objects'] as $object) {
@@ -345,159 +496,94 @@ function islandora_ingest_form_submit(array $form, array &$form_state) {
   }
 }
 
-/**
- * Gets the configuration used to create the multi-page ingest form.
- *
- * @param array $form_state
- *   The drupal form state.
- *
- * @return array
- *   The configuration used to generate the multi-page ingest forms.
- */
-function &islandora_ingest_form_get_configuration(array &$form_state) {
-  return $form_state['islandora']['configuration'];
-}
-
 /**
  * Gets a reference to the stored NewFedoraObject's.
  *
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  *
  * @return array
  *   A reference to the stored NewFedoraObjects to be ingested when the final
  *   step submits.
  */
-function &islandora_ingest_form_get_objects(array $form_state) {
+function &islandora_ingest_form_get_objects(array &$form_state) {
   return $form_state['islandora']['objects'];
 }
 
 /**
  * Gets a single object from the stored NewFedoraObject's.
  *
- * @note - In our current use case we are only dealing with a single object
+ * @note In our current use case we are only dealing with a single object
  *   ingest, this makes it convenient to access it. Ideally the steps
  *   implementations will be abstracted to be indifferent to what object it's
  *   currently working on. This will act as a placeholder for such
  *   functionality.
  *
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  *
  * @return NewFedoraObject
  *   Returns the 'current' object in the array of NewFedoraObjects, generally
  *   this is only used when there is one object in the list of objects.
  */
-function islandora_ingest_form_get_object(array $form_state) {
+function islandora_ingest_form_get_object(array &$form_state) {
   $objects = &islandora_ingest_form_get_objects($form_state);
   return current($objects);
 }
 
-/**
- * Get a reference to the current step index.
- *
- * @param array $form_state
- *   The drupal form state.
- *
- * @return string
- *   The current step index.
- */
-function islandora_ingest_form_get_step_id(array &$form_state, $step_number = NULL) {
-  if ($step_number === NULL) {
-    return $form_state['islandora']['step_id'];
-  }
-  else {
-    $steps = array_keys(islandora_ingest_form_get_steps($form_state));
-    return $steps[$step_number];
-  }
-}
-
-/**
- * Get the step info of the given step or the current step if none is given.
- *
- * @param array $form_state
- *   The drupal form state.
- * @param int $step
- *   The index of the step to get.
- *
- * @return int
- *   The step info of the requested step if found, NULL otherwise.
- */
-function islandora_ingest_form_get_step_info(array &$form_state, $step = NULL) {
-  $step = isset($step) ? $step : islandora_ingest_form_get_step_id($form_state);
-  $steps = islandora_ingest_form_get_steps($form_state);
-  if (!empty($steps[$step])) {
-    return $steps[$step];
-  }
-  // @todo deal with unknown case.
-  return NULL;
-}
-
 /**
  * Get general storage for the given/current step.
  *
  * @param array $form_state
- *   The drupal form state.
- * @param string $step_id
+ *   The Drupal form state.
+ * @param array $step_id
  *   The ID of the step.
+ *
+ * @return array
+ *   The given/current step storage if found, NULL otherwise.
  */
 function &islandora_ingest_form_get_step_storage(array &$form_state, $step_id = NULL) {
-  if ($step_id === NULL) {
-    $step_id = islandora_ingest_form_get_step_id($form_state);
-  }
-
-  if (!isset($form_state['islandora']['step_storage'][$step_id])) {
-    $form_state['islandora']['step_storage'][$step_id] = array();
+  $step_id = isset($step_id) ? $step_id : islandora_ingest_form_get_current_step_id($form_state);
+  if (isset($step_id)) {
+    if (!isset($form_state['islandora']['step_storage'][$step_id])) {
+      $form_state['islandora']['step_storage'][$step_id] = array();
+    }
+    return $form_state['islandora']['step_storage'][$step_id];
   }
-
-  return $form_state['islandora']['step_storage'][$step_id];
+  return NULL;
 }
 
 /**
- * Get a reference to the steps stored in the form state.
+ * Gets the configuration used to create the multi-page ingest form.
  *
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  *
  * @return array
- *   All the steps to be used in the ingest process.
+ *   The configuration used to generate the multi-page ingest forms.
  */
-function islandora_ingest_form_get_steps(array &$form_state) {
-  return islandora_ingest_get_steps($form_state);
+function &islandora_ingest_form_get_shared_storage(array &$form_state) {
+  return $form_state['islandora']['shared_storage'];
 }
 
 /**
  * Call form_load_include, for the current step if it defines a required file.
  *
  * @param array $form_state
- *   The drupal form state.
+ *   The Drupal form state.
  */
-function islandora_ingest_form_step_form_load_include(array &$form_state) {
+function islandora_ingest_form_load_include(array &$form_state) {
   form_load_include($form_state, 'inc', 'islandora', 'includes/ingest.form');
-  $step_info = islandora_ingest_form_get_step_info($form_state);
+  $step = islandora_ingest_form_get_step($form_state);
   // Load include files.
-  if (isset($step_info['file']) && isset($step_info['module'])) {
+  if (isset($step['file']) && isset($step['module'])) {
     $matches = array();
-    preg_match('/^(.*)\.(.*)$/', $step_info['file'], $matches);
+    preg_match('/^(.*)\.(.*)$/', $step['file'], $matches);
     list($file, $name, $type) = $matches;
-    form_load_include($form_state, $type, $step_info['module'], $name);
+    form_load_include($form_state, $type, $step['module'], $name);
   }
 }
 
-/**
- * Get the number of steps.
- *
- * @param array $form_state
- *   The drupal form state.
- *
- * @return int
- *   The number of steps.
- */
-function islandora_ingest_form_get_step_count(array $form_state) {
-  $steps = islandora_ingest_form_get_steps($form_state);
-  return count($steps);
-}
-
 /**
  * Buildes the initial list of ingest steps.
  *
@@ -512,40 +598,26 @@ function islandora_ingest_form_get_step_count(array $form_state) {
  *   The list of sorted ingest steps as defined by all implementers
  *   of ISLANDORA_INGEST_STEP_HOOK.
  */
-function &islandora_ingest_get_steps(array &$form_state) {
+function islandora_ingest_form_get_steps(array &$form_state) {
   module_load_include('inc', 'islandora', 'includes/utilities');
   $steps = &drupal_static(__FUNCTION__);
-
-  if (!isset($steps)) {
-    $steps = array();
-    $configuration = islandora_ingest_form_get_configuration($form_state);
-    $models = array();
-    if (isset($configuration['selected_models'])) {
-      $models = $configuration['selected_models'];
-    }
-    elseif (isset($configuration['models'])) {
-      $models = $configuration['models'];
-    }
-
-    foreach (islandora_build_hook_list(ISLANDORA_INGEST_STEP_HOOK, $models) as $hook) {
-      // Need to pass by ref...  But don't really want an alter.
-      foreach (module_implements($hook) as $module) {
-        $function = $module . '_' . $hook;
-        $module_steps = (array) $function($form_state);
-        $steps = array_merge($steps, $module_steps);
-      }
-    }
-
-    // Remove NULL values.
-    $steps = array_filter($steps);
-    uasort($steps, 'drupal_sort_weight');
-    foreach (islandora_build_hook_list(ISLANDORA_INGEST_STEP_HOOK, $models) as $hook) {
-      $form_state_copy = $form_state;
-      drupal_alter($hook, $steps, $form_state_copy);
+  if (isset($steps)) {
+    return $steps;
+  }
+  $steps = array();
+  $shared_storage = &islandora_ingest_form_get_shared_storage($form_state);
+  foreach (islandora_build_hook_list(ISLANDORA_INGEST_STEP_HOOK, $shared_storage['models']) as $hook) {
+    // Required for pass by reference.
+    foreach (module_implements($hook) as $module) {
+      $function = $module . '_' . $hook;
+      $module_steps = (array) $function($form_state);
+      $steps = array_merge($steps, $module_steps);
     }
-
-    uasort($steps, 'drupal_sort_weight');
   }
-
+  $steps = array_filter($steps);
+  foreach (islandora_build_hook_list(ISLANDORA_INGEST_STEP_HOOK, $shared_storage['models']) as $hook) {
+    drupal_alter($hook, $steps, $form_state);
+  }
+  uasort($steps, 'drupal_sort_weight');
   return $steps;
 }
diff --git a/includes/ingest.menu.inc b/includes/ingest.menu.inc
index ca4f6156..a6f79891 100644
--- a/includes/ingest.menu.inc
+++ b/includes/ingest.menu.inc
@@ -12,19 +12,20 @@
  *   HTML representing the mult-page ingest form.
  */
 function islandora_ingest_callback() {
-  $configuration = islandora_ingest_get_configuration();
-  if ($configuration === FALSE) {
-    drupal_set_message(t('Invalid ingest configuration.'), 'error');
+  module_load_include('inc', 'islandora', 'includes/ingest.form');
+  try {
+    $configuration = islandora_ingest_get_configuration();
+    return drupal_get_form('islandora_ingest_form', $configuration);
+  }
+  catch(Exception $e) {
     $redirect = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '<front>';
     // Redirect back to referer or top level collection.
     drupal_goto($redirect);
   }
-  module_load_include('inc', 'islandora', 'includes/ingest.form');
-  return drupal_get_form('islandora_ingest_form', $configuration);
 }
 
 /**
- * Fetches/validates the ingest configuration from the $_GET parameters.
+ * Fetches the ingest configuration from the $_GET parameters.
  *
  * Generic parameters as accepted by all ingest processes, other modules may
  * add to this list.
@@ -44,22 +45,5 @@ function islandora_ingest_get_configuration() {
   foreach ($convert_to_array_keys as $key) {
     $configuration[$key] = explode(',', $configuration[$key]);
   }
-  // @todo add hook for manipulating/validating the configuration.
-  return islandora_valid_ingest_configuration($configuration) ? $configuration : FALSE;
-}
-
-/**
- * Validates the given ingest configuration.
- *
- * At the moment it requires that models and collections are present.
- *
- * @param array $configuration
- *   The key value pairs that are used to build the multi-paged ingest process.
- *
- * @return bool
- *   TRUE if the configuration is valid, FALSE otherwise.
- */
-function islandora_valid_ingest_configuration(array $configuration) {
-  // @todo Add more robust validation, add watchdog logs, etc.
-  return isset($configuration['models']) && isset($configuration['collections']);
+  return $configuration;
 }