Richard P. Feynman was a theoretical physicist whose contributions to quantum physics earned him the 1965 Nobel Prize in Physics (along with Julian Schwinger and Shinichiro Tomonaga). Feynman, along with Robert Leighton and Matthew Sands, authored a three-volume textbook entitled The Feynman Lectures on Physics, based on a series of lectures he delivered to his students at the California Institute of Technology between 1961 and 1964. Today, Caltech's Division of Physics, Mathematics, and Astronomy and the Feynman Lecture Website makes all three volumes of this textbook freely available for anyone interested in reading the textbook. Importantly however, the site emphasizes that while readers are welcome to explore the lectures online, they do not have permission to download these texts. Visitors can explore each chapter (or lecture) in this series with ease via each volume's table of contents. Topics covered include Newton's laws, the theory of gravitation, and quantum behavior.