Instruct: Classify a given review as either positive or negative.
Query: not very good as a reference

This book may be useful if you plan to study each chapter thoroughly, or even go through the whole book, but it should definitely not be purchased as a reference. The index is woefully thin -- a mere 6 pages -- which is extremely unusual and, IMHO, unacceptable for a book about a programming language. (I chose a C++ book at random from my shelf and it has a 37 page index, which one would expect from any useful programming book.) Because of this inadequacy, I think the high cost of the book is unjustified.