Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Use as a last resort only

I bought the book after meeting Ms. Carasik at the RSA conference last March. It is useful as a high level overview, but one cannot trust the details. In some places, the author appears to simply make stuff up. For example, on p118, the SSH_AUTH_SOCK variable is correctly defined but is also claimed to be related to the SOCKS network proxy. On p243, it is suggested that the reader use "something like Perl or a shell script" to generate the random number needed for setting up X authentication. I had to search the Web to find a one-line perl expression to do this, and then I had to refer to volume 8 of my O'Reilly X set to figure out how X authentication really works. Very disappointing!If I were in the market for a Secure Shell book today, I'd wait for the new one coming from O'Reilly. Use this one only as a last resort and only if you mostly know what you're doing.