Wireshark Fundamentals
Vinit Jain
Building Secure and Reliable Systems
Heather Adkins & Betsy Beyer & Paul Blankinship & Piotr Lewandowski & Ana Oprea & Adam Stubblefield
tmux (for Diego Cohen)
Brian P. Hogan
Mastering Linux Administration
Alexandru Calcatinge & Julian Balog
Certified Ethical Hacker (CEH) Exam Cram
William Chuck Easttom