Linux Advanced Routing and Traffic Control HOWTO
Gregory Maxwell & Remco Mook & Martijn Oosterhout & Paul Schroeder & Jasper Spaans & Bert Hubert
Mastering OpenLDAP
Matt Butcher
tmux (for Diego Cohen)
Brian P. Hogan
How Linux Works, 3rd Edition
Brian Ward
The Wireshark Field Guide
Robert Shimonski