A formula for success:
1. Put together an idea and outline for a book that hasn't been covered in-depth before.
2. Gather three of the most talented WordPress developers/writers and have them write the book.
3. Release the book and watch the Elves return back to Middle Earth to rejoice with men.
Professional Plugin Development, written by Ozh Richard, Justin Tadlock, and Brad Williams, is a much-needed and very timely book.
There have been several aspiring developers that have approached me saying they needed a start-from-the-basics WordPress plugin development book. And while Professional Plugin Development does teach the basics of plugin development, it quickly moves on to much more complex topics.
The book covers the topics I care most about, such as:
* WordPress Plugin Foundation and Best Practices
* WordPress Security
* WordPress Actions and Filters (aka, hooks)
* And Ajax
But the book goes beyond basic plugin development. It teaches you about plugin options, CRON for scheduling common tasks, storing data (whether it is via post types, transients, or options), the HTTP API (for retrieving remote data), users (how to set up roles and capabilities), localization (err, internationalization), and how to test plugin performance.
For a novice PHP and WordPress developer, this is a good starting point. But don't think of this book as your way to learn PHP, jQuery, or even basic WordPress (there's WordPress for Dummies for that).
This is a book written by developers for developers. And I must say that I learned a lot from this book, and I've been developing WordPress plugins and themes for almost six years.
Here are the things I learned most from this book:
* The Why. I've used a lot of the techniques from the book before, but now I have a better understanding of why the techniques should be implemented. An example is security and WordPress coding best practices.
* Rewrites and Cron. These two topics escape me (no pun intended) for some reason, but I have a much better understanding of how everything works behind the scenes.
* Security. Security can not be stressed enough, and very solid security tips are sprinkled throughout the book (and the topic even receives treatment via its own dedicated chapter).
* Multisite. I've been working with multisite for almost a year now, and it's a topic I'm still learning in-depth. The chapter gives a great explanation of terms and common pitfalls.
Last, but certainly not least, the book goes into great detail for what you should do after you've released a plugin, whether you want to release it for free in the official WordPress repo, or have it available exclusively on your own site (whether commercial or free). The book explains marketing, how to set up automatic updates (albeit a bit glossed over), and how to get the plugin on the official repo.
This is a highly recommended book, whether it be the print version, or digital.