Those pale blue hardcover Unix books are quite excellent, made for this job. Best would be to hide possibly embarrassing, smaller, books in there. Crap du jour "in a nutshell", that sort of stuff. On the outside, you are a gray beard, reading Stevenson and knowing the ins and outs of Unix Networking, TCP/IP, and System Calls, but on the inside, the secret of your actual software career "in a nutshell" is laid bare in secret compartments.