Ask Cisco what the time is and they'll tell you how to build a watch! Sound familiar?
Unlike all other Cisco books I have, this guide explains a topic and then gives several real-world examples, and I mean real-world not a silly Cisco lab setups.
Using this 1 book I have configured NAT/PAT, CBAC, IDS, VPN across our companies Cisco routers.
My only critism is the VPN section is too brief with no remote access VPN examples. It could also do with an AAA section.
If you are an overworked admin that doesn't have time to read huge volumes of technical information buy this book!!