It's not a big book so my expectations were low. I wouldn't exactly classify it as "advanced" either.
There is an introduction, followed by lines of code, followed by table of lines and respective function in lay terms. Although I was able to extract a few gems, it's not formatted as a reference and therefore not a good resource to use on the fly.
I can't really recommend the book, except for passive reading. Online PHP resources offer much more as a practical reference.