"The whole thing was basically an experiment," said Richard Feynman late in his career, looking back at the roots of his lectures. The experiment proved to be extremely successful, spawning publications that remain definitive and introductory for physics for decades. From the basic principles of Newtonian physics to theories such as general relativity and quantum mechanics, Feynman's lectures are a monument of clear formulation and deep understanding. Timeless and collectible, the lectures are essential reading, not only for physics students but also for anyone seeking an introduction to the field by the unparalleled Feynman.