There are many books available for learning PHP, but they can quickly become outdated in a short period of time. Included here is a quick list of PHP books you should look into when learning PHP or extending your knowledge. Also keep in mind that writing a very good programming book can take several thousand hours, so supporting their authors is nice way of saying thank you.
- Official PHP manual - Offical PHP manual is also available for offline usage.
- Clean Code PHP - Robert C. Martin's book Clean Code, adapted for PHP.
- PHP: The Right Way - An easy to read, quick reference for PHP best practices, accepted coding standards, and links to authoritative PHP tutorials around the web. "PHP: The Right Way" is also available as a PDF book.
- PHP 5 Power Programming
- PHP Best Practices - A short, practical guide for common and confusing PHP tasks.
- PHP Essentials
- PHP Internals Book
- PHP Pandas - Aims to teach everyone how to be a web developer.
- PHP Programming
- PHP Security Guide
- Practical PHP Programming
- Practical PHP Testing
- Survive The Deep End: PHP Security - PHP Security
- Wikibooks PHP Programming - A PHP programming book on Wikibooks.
- Using Libsodium in PHP Projects - A guide to using the libsodium PHP extension for modern, secure, and fast cryptography.
- Build APIs You Won't Hate
- Building Secure PHP Apps
- Iterating PHP Iterators
- Learnable: PHP Master: Write Cutting-edge Code
- Modern PHP: New Features and Good Practices
- Modernizing Legacy Applications In PHP
- PHP Objects, Patterns, and Practice
- Practical Design Patterns
- Securing PHP: Core Concepts
- Securing PHP: Usual Suspects
- Scaling PHP
- Signaling PHP
- The Grumpy Programmer's Guide To Building Testable PHP Applications
- Typed PHP
- O'Reilly: PHP Books