I'll keep the review limited:
The book covers the basics well -- you get a rather nice (highly informative for the newbie) explanation of TCP/IP and various protocols that go with it. You learn to think less about how IP operates and more about how the individual programs operate (i.e. UDP vs TFTP) It really makes you think more about each program that goes across the network.
The real benefits come from what you gain in skill with Wireshark. The book teaches you some stuff that even the more experienced users may be wowed by.
All things considered, I don't regret the purchase. The book is a worthwhile read. Highly recommended to anyone who's new with packet analysis.