DEAR READER, thank you for picking up this book! You have probably heard about WordPress already, the most popular self - hosted content management system (CMS) and blogging software in use today. WordPress powers literally millions of Web sites on the Internet, including high profi le sites such as TechCrunch and CNN ’ s blog. What makes WordPress so popular is that it ’ s free, open source, and extendable beyond limits. Thanks to a powerful, architecturally sound, and easy - to - use plugin system, you can customize how WordPress works and extend its functionalities. There are already more than ten thousand plugins freely available in the offi cial plugin repository, but they won ’ t suit all your needs or client requests. That ’ s where this book comes in handy!

As of this writing, we (Brad, Ozh, and Justin), have publicly released 50 plugins, which have been downloaded nearly one million times, and that ’ s not counting private client work. This is a precious combined experience that we are going to leverage to teach you how to code your own plugins for WordPress by taking a hands - on approach with practical examples and real life situations you will encounter with your clients.

The primary reason we wanted to write this book is to create a preeminent resource for WordPress plugin developers. When creating plugins for WordPress, it can be a challenge to fi nd the resources needed in a single place. Many of the online tutorials and guides are outdated and recommend incorrect methods for plugin development. This book is one of the most extensive collections of plugin development information to date and should be considered required reading for anyone wanting to explore WordPress plugin development from the ground up.