First of all, the video lectures were so engaging that I, who has ADHD, watched 30% of them in one day. Even concepts that seem somewhat abstract to junior developers, such as SOLID principles and object-oriented, were explained in an easy-to-understand manner with examples, which reminded me of a mother bird. In this lecture, I felt that the maestros who definitely knew the truth had concise and simple sentences. It felt like eating a well-prepared Korean meal. I felt the same way when I listened to Object's Cho Young-ho's offline lecture, but Toby's lectures were so natural and logical that I felt like he had prepared a script. Of course, I don't think there is a royal road to learning development. However, with this level of compass, I don't think I'll get lost. Also, the way he explains complex concepts in an easy-to-understand manner was a great help in my studies. Through this lecture, I was able to approach difficult concepts with confidence. And as a side note, this is something I didn't expect because I only read books, but Toby's voice had the power to increase concentration and immerse me. I really liked his calm yet powerful voice.