Though the title implies it, this book is not really a sequal to the Six Easy Pieces. They can be read seperately. It treats some of the concepts centered around Special and General Relativity that revolutionized physics near the turn of the century. It would be impossible to find another book that can dive so deeply into topics such as symmetry and space-time, while bypassing formalism and exposing the fundemental ideas and signficance in every-day terms. The delivery is in lecture form, and while that makes it more authentic and real, the fact that this is a book and the reader is not really in a lecture, makes it a little awkward. One often gets the feeling that one had to be there to get the full benefit. There is little attempt at explaining the historical context and other niceties and focus is solely on the concepts themselves. One needs to have at least college level math background to follow the derivations. Feynman has done a phenomenal job in reducing such complex concepts into digestable pieces of conversation. There is no abstraction, everything is quantified. I especially enjoyed the chapter Curved Space, as I had never seen it treated so intimately. The self consistency of all these topics and how they are interrelated is elegantly presented.