It's good for beginners. In fact, there are only a few old system hacking books on the market, so I borrowed them from the library and read them, and then I watched this lecture on YouTube. I understood everything I didn't understand from the book. I think it's the best for beginners now that there aren't many system hacking lectures in Korean... I also watched the instructor's Lena tutorial and Python lecture, and he teaches well... Highly recommended.