If you want to learn network information security by yourself, it is recommended that you first understand the basic concepts and terms of information security. You can refer to the following books: Introduction to Information Security Computer Network Security Operating System Security 4 The authoritative guide to Web application security 5. Basics of Cryptology These books were classic textbooks in the field of information security, covering all aspects of information security, including network security, data security, application security, and so on. Next, he could choose the areas of interest according to his own interests and needs to study in depth. For example, if you are interested in network security, you can study books such as Introduction to Network Security, Computer Network Security, Attack and Defense, and the authoritative guide to Web security. In addition, you can also participate in relevant training courses and certification exams such as Crism, CISSS, CEH and other certificates. These certificates could prove that having certain information security knowledge and skills would be helpful for future career development. In short, learning network information security requires continuous learning and practice. I suggest that you persist in learning and reviewing every day. You should participate in relevant communities and forums to exchange experience and knowledge with other information security engineers.