This book is 520 pages devoted entirely to SSH! It includes detailed coverage the history of SSH and the underlying network and cryptographic mechanisms which make up the SSH protocol. It also shows you in fairly explicit detail how to set up everything from password-less logins to complex encryption tunneling schemes. If you use SSH alot and find yourself wishing you could fully utilize it's features, this book is for you.

This book is my Secure Shell reference. For OpenSSH it has pretty much everything I'm ever likely to need to know and I found it an interesting read.

It doesn't have quite the same level of detail on commercial SSH products (e.g. from ssh.com or F-secure), but then both those have good product documentation themselves so it's less critical.

There were a couple of areas I found a little less clear than they could be. Tunnelling, for example,is explained in detail but somehow still doesn't come out as a clear and easily understandable explanation.

These are the exception rather than the rule though and there's no other book I'd rather have for SSH information.