Embedded systems may seem easy to learn on the surface, but it is surprisingly rare to find cases where the fundamental principles are properly understood. Working in the field, I often see how this difference in "basic skills" eventually leads to a gap in overall expertise. As the title suggests, this lecture points out the "essence" of embedded systems very sharply and clearly. Since the instructor has a deep insight into the core topics, I felt that concepts that could feel complex and overwhelming were being systematically organized in my head. I highly recommend this to not only those who are just starting out in embedded systems but also to junior developers who want to solidify their foundations once again.