It's a textbook a friend recommended me, and it's great for learning the conceptual workings of an operating system, and it has practical knowledge alongside the conceptual. Code examples are written in C. If thou art interested in Operating Systems, this is a highly informative and interesting textbook thou shouldst check out!
I can learn information & skills extremely quickly, and I get to choose what I hyperlearn and what I regular learn (for example, I can basically flip through the DSM 5 and memorize everything, or watch a tutorial on 2x skill and nail it first try)