In short a book you can take out of your wishlists, no value for your money, all the data is available in at least the same level or better for free on the PayPal developer website.
I had some expectations when I downloaded this book, for a long time I have wanted to do a small PayPal integration project, just to flex my eCommerce muscles, I thought doing it on such an important platform would be a great experience, and so I was very happy to see this book on the list.
However, reading the book, I found little information of interest about the different APIs available, and hardly any information that explains the logic and the options of the PayPal API. it is mostly a LOT of source code which does the same thing again and again, with no added value per example. Not enlightening, no special tips or gotchas - just function by function rundown of the API (what you could get by reading the attached documentation from the Developer site).
I expected a lot more, more about eCommerce, more about security, more about integration with a working site (which the book mentions but never gets around to showing).
Do not waste your money.