This is the first book I have read in preparation for the I-Net+ certification exam. Due to the many inaccuracies, I will have to cover at least one more prep guide before I feel ready to take the exam. While some of the chapters are well-written, the book as a whole is very poorly edited: the same concepts are described in more than one chapter, and terms and concepts are used freely before they have been explained. Also, as other reviewers have noted, there are many inaccuracies and mistakes - my favourite is the diagram of the 7 layer OSI/RM model that shows 6 layers. Additionally, the writer of the Network and Server chapters (I'm sure it's the same person) should be a poster-child for how NOT to write a technical manual - those chapters are gorgeous examples of dense, turgid and unnecessarily incomprehensible writing. I intend to use excerpts in my Technical Writing seminars.