This is the PHP 5 book for PHP 4 programmers. If you're currently using PHP and want to learn what's new in PHP 5, you should buy this book. Unlike other PHP 5 books, Upgrading to PHP 5 assumes you're familiar with PHP, so it doesn't waste your time discussing how to process forms and query databases.
Instead, Upgrading to PHP 5 shows you a complete collection of detailed examples covering all the latest and greatest features of PHP 5. Object-oriented programming? Check. MySQL? Check. XML? Check. If it's part of PHP 5, it's part of this book.
Besides showing off PHP 5, this book also eases your migration from PHP 4 to PHP 5. As a veteran PHP programmer, you have pages and pages of existing PHP code. Not all of it will work perfectly under PHP 5. That's why Upgrading to PHP 5 provides you with detailed side-by-side comparisons of PHP 4 and PHP 5 solutions. This lets you clearly see the exact changes you need to make to your current code.
In addition to covering what's new and how it's new, this book tells you why it's new. PHP 5 isn't change for the sake of change. Upgrading to PHP 5 explains the logic behind the changes and shows how you can take advantage of them to the benefit of your code.
Finally, it provides an address book program. This concrete example combines the new features of PHP 5, demonstrating their usefulness in the context of a complete application. The address book shows you exactly how PHP 5 makes it faster and easier to develop more powerful and flexible web applications.