I bought this book to help gain my CCDA and found it to be lacking in detail required by the exam. As the previous reviewer said, certain topics are not covered in enough detail to answer the questions posed by the exam(IPv6 and Voice are major issues on the exam but are not discussed in enough depth).
The content of the book is worth knowing and is all good background knowledge and will aid anyone who needs to design networks as part of their job. The 'mock' exam questions, however, are far removed from the reality of a Cisco test and will give a false confidence to prospective candidates.
The book spends a great deal of time discussing Routing Protocols in specific detail, but questions asked in the exam are very general towards them, meaning that candidates will spend too much time focusing on them. Also, Cisco IOS commands are discussed - this will help in a practible sense but in respect of the exam is a waste of time as they are not required.
In my opinion this book is worthwhile, and a good source of information, however, it is not sufficient to pass the exam it is meant to address. This is the main problem as people will be investing in it purely for this reason. For this reason, I cannot reccomend it to other candidates.