Online Classes Instead of Books I'm a 15-year developer. This time, I had to develop an API server using Spring Boot. As I usually do, I bought a bunch of Spring Boot, Spring Security, and OAuth cookbooks and piled them up on my desk to study. I didn't know how to use them in practice, so I couldn't figure out if they were right or wrong and how to apply the contents of the books. After wandering around like that, I bought Baek Sun-seon's Inflearn course. I bought it because the reviews were good and I wanted to listen to it lightly before going to bed. Huh? Huh????? Huh?????? After listening to the course, I felt like my chest was unblocked. It covers everything from TDD, RESTful API, Spring Boot, Spring Security, and OAuth, and it was all good enough to be applied directly to this project. From now on, instead of looking for books first when I study something new, I think I'll look for these great video courses first. I'm recommending it to everyone around me. If you have time, I hope that a course related to "OAuth social login and Spring Security" that is widely used in the industry these days but has ridiculously little information will be added somewhere. I sincerely thank you for creating such a great course. I'm going to go on a Baek Sun-seon course tour.