I've looked at study books for VCP, and have easily found errors in them, and sometimes many errors. I wouldn't buy one. There is no substitute for using the exam blueprint, official documentation, and the software to do the things you will get tested on. Mastering vSphere is a great reference book, and great at explaining concepts that you might not understand, but I'd question it's value as an out and out study book for VCP.

Scott.