In short: great overview of the various tools and processes that can be followed to make working in PHP easy and manageable. I have a new employee here in the office who will be getting this book after me, to quickly bring her up to speed on good practices.
As you might guess from the "new employee" comment, even though the word "Expert" is in the title, you don't need to be an expert PHP programmer to use this book. It's an all-round overview of the programs you might use during your day-to-day programming life for the next few years.
As the author (Dirk Merkel) suggested in the book, some people may disagree with some choices in the book. For example, I am a fervent Vim user, but the book chooses Eclipse as its programming environment of choice.
From a broader point of view, the Eclipse IDE may be the correct one for programmers to use, as it offers much more than just a text editor. As for me, it's hard to change an old dog's habits!
The book includes some handy reference notes for various tools, such as SVN or phpDocumentor. It's good for people that are not used to reading online references for everything to have them all in one book.
Each chapter is immensely in-depth. To the point that it's almost like each chapter is a mini-book on its own subject. In some cases the chapters include everything you might ever use on those subjects.
For myself, I'm interested to try some of the suggestions in the Continuous Integration chapter and throughout the book, as I already run a few projects where updates are more important than releases. I'm especially interested in integrating SVN with automated testing and style-checking. Test-driven Development is described in the book, and it certainly seems more robust than my current "deadline-driven development" style!
There were code samples in there that could have been shortened immensely by choosing a different spacing scheme or reducing the comments. For example, in the Debugging chapter, there is a code sample that goes on for 9 pages. That's a lot of code to read... If the empty lines and comments had been removed or reduced, Dirk could have cut it down to maybe 4 or 3 pages, making it much more readable in print. As it was, I did my best to read through it, flipping back and forth between pages to find where references went or came from.
Immensely useful for the professional programmer. Especially a programmer who needs to fit into a team. I'm no beginner myself, and picked up quite a few tips throughout the book.
Buy this book - it's worth it.