Chapter 3. Hooks, Actions, and Triggers, Page 48

Location on the page: 
Heading half way down page
Chapter: 
3. Hooks, Actions, and Triggers
Error: 

Changing Existing Actions with drupal_alter

Correction: 

Changing Existing Actions with hook_action_info_alter

Description of the Error: 

drupal_alter is a generic dispatching mechanism used for many hooks. That it is used to dispatch hook_action_info_alter is an irrelevant and confusing implementation detail. (Note: the same error should be corrected in the comment for the code example beneath the heading.)