Of all the physics textbooks currently available on the market, this one seems to be the best at explaining phenomena and challenging the reader to think creatively about the material. The only gripe I can possibly give about this series is that there is a distinct lack of problem sets, which can lead to more artistic studying rather than actually putting the legwork into understanding physics. This can be solved by purchasing one of the many books out there that are almost entirely problems, and using them to help you keep up with Feynman's lectures.