SELinux Coloring Book by Dan Walsh and Mairin Duffy [source]
SELinux stands for Security-Enhanced Linux and it is a Linux security kernel module. Linux box without SELinux is not secure. Read this coloring book to understand how SELinux works.
Why Most Unit Testing Is Waste by James O Coplien [source]
Twenty-one pages paper that you must read in order to understand Unit testing.
Crash Course in DDoS Mitigation by Imperva [source]
DDoS stands for denial of service. In a fun, quiz-based online format, these free training courses give you the technical knowledge and skills to identify and block different types of DDoS attacks.
Manual Testing, The Art That Cannot Be Lost by Joseph Millar [source]
Joseph gives a story about how testing is both manual and automated activity.
How to come up with test ideas by Eric Brickarp [source]
Awesome collection of resources on how to improve your testing. Bookmark it and start using it!
What are the most important software quality assurance techniques? by Gerald Weinberg [source]
Yes, Jerry is still with us! By answering this question, Jerry provides links to his awesome books that answer this question.