This is a delightful booklet. It contains the handwritten notes prepared by Fermi for his lectures at Chicago. They are marvellously organized, with all derivations clearly given, together with the motivations and examples. Sometimes you find a note like that: "Comment on the relative cosmological abundance of elements", and you can only imagine what the master would produce. The table of contents of the book is quite usual, and corresponds more or less to a book like Schiff, Merzbacher, etc, with more emphasis on applications. It is one of the best examples of the Fermi mastery of teaching techniques, using simple models, approximations, clever analogies. The book, as one should expect, contains the best derivation of the "Fermi Golden Rule", which is a formula for the rate of transitions in first-order, time-dependent perturbation theory. Fermi used to make miracles with this formula. The essential difference between this book and the usual intro! ductory ones is, of course, Fermi. This means that the problems are treated as they really appear in nature, with no idealizations to make things easier. Fermi could do that as no other physicist, as he was the last universalist: there was a time in which it was not unreasonable to say that he was the best theoretician and the best esperimentalist in activity.A similar set of notes about thermodynamics and statistical physics was offered also by the University of Chicago Press.I wonder if they are still available.