Wordpress | Learn | Chapters | Introduction to Plugin Development

Here is the link. 

1. Introduction to plugin development
2. Plugin basics
3. Plugin security
4. Hooks - Actions, Filters, Custom hooks, Advanced topics
5. Privacy
6. Administration Menus
7. Shortcodes - Basic shortcodes, enclosing shortcodes, shortcodes with parameters, TinyMCE enhanced shortcodes
8. Settings
9. Metadata
10. Custom post types
11. Taxonomies
12. Users
13. Http API
14. JavaScript, Ajax, & jQuery
15. Cron
16. Internationalization
17. The plugin directory
18. Developer tools 
19. Credits