This book is filled with practicle examples of troubleshooting. It begins with the osi model, but not in a dry accademic way - it actually tells you how the things work, and why. The book then moves to a discussion of protocols, tcp, ip, ipx, spx, udp, and stuff like that. Then it goes into looking at traffic on the network. Frist from the client side, then to the server side of things. After all that, it talks about using Microsoft's Network Monitor product - tells all the ins, and the outs of the product. Finally, it concludes with tons of troubleshooting scenarios. The book is informative, and actually fun to read.