Cisco CallManager Best Practices is a very well written book with plenty of useful information. However, please note, this is not an introductory book for Cisco IP Telephony. As its name implies, this book provides "best practices" for installing, running and optimizing an IP Telephony network. Thus, this book should be used by experienced IP Telephony engineers in order to plan new deployment or optimize existing IP Telephony networks.
Beyond that one caveat, I highly recommend this book. It is well written and has very good information. I did not find any errors and found the technical information very in-depth and thorough.
I particularly liked Chapter 6: Securing the Environment. While obviously slanted toward IP Telephony, this chapter provided detailed security practices that should be applied to all networks. This chapter focuses on how overall network security leads to secure IP Telephony environments, which is the way security should be approached. By simply securing your IP Telephony assets (CallManagers, Gateways, etc), but not implementing standard security technologies (private VLANs, ARP inspection, 802.1x, etc) engineers will still leave their IP Telephony network subject to attack. Rightfully so, this chapter explains how IP Telephony is just a part of overall security, and then explains basic security technologies with an inkling toward IP Telephony.
My only complaint about this book, and why it only received 4 out of 5 stars, was its lack of flow. Chapters did not build on one another, despite appearing that way from the Table of Contents. Each chapter started fresh. However, I think this may be a factor of the book's purpose: providing "Best Practices" and not laying out a step-by-step process for IP Telephony deployments. As I mentioned above, this is not a book to use for someone new to IP Telephony or for your first deployment. This book should be used by experienced IP Telephony engineers to enhance their knowledge for new deployments and bolster existing IP Telephony networks.
Michael J. Morris
CCIE #11733, MCSE