STARTING OUT as a simple blogging system, over the last few years WordPress has morphed into a fully featured and widely used content management system. It offers individuals and companies world-wide a free and open-source alternative to closed-source and often very expensive systems.

When I say fully featured, that's really only true because of the ability to add any functionality needed in the form of a plugin. The core of WordPress is simple: You add in functionality with plugins as you need it. Developing plugins allows you to stand on the shoulders of a giant: You can showcase your specific area of expertise and help users benefit while not having to deal with parts of WordPress you don't care or know about.

I've written dozens of plugins, which together have been downloaded millions of times. Doing that has changed my life. It has helped me build out a business for myself, doing development and (SEO) consultancy work. This is in your outreach too!

I wish that when I started developing plugins for WordPress as a hobby, some five years back, this book had been around. It would have saved me countless hours of digging through code and half-finished documentation. I always ended up redoing pieces because I'd found yet another best practice or simply an easier way of doing things.

Although this book didn't exist yet, the authors of this book have always been a source of good information for me while developing my plugins. Each of them is an expert in his own right; together they are one of the best teams that could have been gathered to write this book.

WordPress makes it easy for people to have their say through words, sound, and visuals. For those who write code, WordPress allows you to express yourself in code. And it's simple. Anyone can write a WordPress plugin. With this guide in hand, you can write a plugin that is true to WordPress' original vision: Code is Poetry.

Happy coding!

Joost de Valk

Yoast.com