PHP *needs* capable writers, like this one. Developers, who take time to write, seem rare - compared to writers, who rarely get to do development projects, anymore. This author is clearly a very experienced practitioner. He outlined a great table of contents.
He advocates and provides guidance for adhering to best practices, regarding design patterns, scalability, caching, unit testing, profiling & tuning etc. The last 1/6 of the book is about C language PHP extension. Excellent "Further reading" suggestions are provided at the end of each chapter.
Out of a high-volume PHP site developer, since 1999, I would expect creative examples. If your site provides Fibonacci sequences and readability scores web services, you'll find this book highly useful. Though on page 1, the author PROMISES NO* "foo-bar" examples, he provides plenty (on pages: 19, 53, 56, 68, 102, 158, 166, 227, 230, 255, 268, 274, 325, 373, 405, 466, 483, 484, 563). Since a reader devotes plenty of time to contemplating foo-bar examples, I came to realize why they bother me so much ... they're unimaginative (i.e. mentally lazy), regarding pragmatic applications for the technology.
I found myself constantly marking comma's in the text - to ease the readability and follow what was being said. If the author doesn't know where to put comma's, the editors should! There's no bold text - to illustrate lessons within the code. As far as I can remember, there's no offer of complete code (e.g. from a website), either.
This is a good, author with generally readable writing style and a wealth of experience to convey. I wouldn't dissuade anyone from buying this book; there's a tremendous amount to be learned and gained from this ... probably the most advanced PHP text, available. I'm just a bit disappointed, because, though it's very good, it could have been world class. I would buy future books from this author; I hope that they get even better!