I've listened to many other instructors, but John Ahn definitely stands out. 0. Low price policy (Cloned lectures are basically formed at 50,000~60,000 won or more. It's almost an ecosystem destroyer price policy; ) 1. Sincere lecture materials (There are many instructors who do not upload lecture materials, saying that they are their own copyright... ) 2. Fast and sincere Q&A that comes within 1~2 days (In other lectures, there are many instructors who do not even reply because the content is slightly different from the lecture.. ) 3. Explanations without unnecessary or useless words (They do not say strange things. There are many instructors who talk as if they know about parts that they do not know or are inaccurate, but I like the fact that they explain things easily for beginners and refrain from talking about difficult concepts. ) 4. Internalization of concepts through repeated learning (They never copy and paste, saying that they did this once and did this. Of course, in the latter half of the lecture, their own efforts and repetition are essential, but they organize the concept and necessity of Redux themselves. ) 5. Good voice (An attractive, low-mid tone ) If you really want to start front-end and back-end, this is a roadmap worth following. Highly recommended. Caution) However, if you are a complete beginner, please listen to John An's free lecture first. It is greedy to listen to this lecture first when you don't know anything.