The Feynman Lectures on Physics

The Feynman Lectures on Physics is a three-volume textbook drawn from a series of lectures given by Richard Feynman, a Nobel Prize winner frequently referred to as "The Great Explainer." The lectures were delivered to undergraduate students at the California Institute of Technology (Caltech) between 1961 and 1964. Feynman co-authored the book with Robert B. Leighton and Matthew Sands. A 2013 review in *Nature* praised the work for its "simplicity, beauty, unity … presented with enthusiasm and insight."

The first volume covers mechanics, radiation, and heat, including relativistic effects. The second volume is primarily about electromagnetism and matter. The third volume addresses quantum mechanics, using the double-slit experiment to illustrate the core features of the field. The book also contains chapters on the relationship between mathematics and physics, and on how physics connects to other sciences. In 2013, Caltech, in partnership with The Feynman Lectures Website, made the book freely accessible online.

By 1960, Feynman’s research had resolved several major inconsistencies in fundamental theories, most notably in quantum electrodynamics, for which he won the 1965 Nobel Prize. Around the same time, Caltech faculty were worried that their introductory courses were outdated and failed to cover recent discoveries, many made at Caltech itself. They decided to overhaul the first physics course to generate more student excitement. Feynman agreed to teach it, but only once. Recognizing the event’s historical significance, Caltech recorded every lecture and photographed each blackboard drawing Feynman made. A team of physicists and graduate students then turned the recordings into a manuscript, which became *The Feynman Lectures on Physics*. Though Feynman’s most important technical contribution was in quantum electrodynamics, these lectures became his most widely read work.

The lectures are regarded as a sophisticated and comprehensive college-level introduction to physics. In his original preface, Feynman admitted he was “pessimistic” about reaching all his students, writing that the lectures were meant “to maintain the interest of very enthusiastic and rather smart students coming out of high schools and into Caltech.” He targeted students who, after two years of the previous course, were “very discouraged because there were really very few grand, new, modern ideas presented to them.” Consequently, some physics students find the lectures more useful after mastering traditional texts, and the books are often seen as more helpful for teachers than for students.

While the two-year course (1961–1963) was still running, word of it spread through the physics community. In a preface to the 1989 edition, David Goodstein and Gerry Neugebauer claimed that registered undergraduate attendance dropped sharply over time, but was offset by a rise in faculty and graduate student attendance. Co-author Matthew Sands, in a memoir accompanying the 2005 edition, disputed this claim. Goodstein and Neugebauer also wrote that “it was [Feynman’s] peers — scientists, physicists, and professors — who would be the main beneficiaries of his magnificent achievement, which was nothing less than to see physics through the fresh and dynamic perspective of Richard Feynman,” and that his “gift was that he was an extraordinary teacher of teachers.”

Addison-Wesley published a collection of exercises and problems to accompany the lectures. These problem sets, first used in the 1962–1963 academic year, were organized by Robert B. Leighton. Some problems are sophisticated enough to require understanding of advanced topics like Kolmogorov’s zero–one law. The original books and supplements contained several errors, some making problems unsolvable; errata were later issued and are now online. Addison-Wesley also released all the lecture audio tapes on CD, totaling over 103 hours, with remastered sound and reordered lectures. A table mapping the books to the CDs was provided. In March 1964, Feynman gave a guest lecture to the freshman physics class, but the notes were lost for years. They were eventually found, restored, and published as *Feynman’s Lost Lecture: The Motion of Planets Around the Sun*. In 2005, Michael A. Gottlieb and Ralph Leighton co-authored *Feynman’s Tips on Physics*, which includes four previously unpublished freshman lectures (three on problem solving, one on inertial guidance), a memoir by Sands about the lectures’ origins, and exercises with answers assigned by Leighton and Rochus Vogt in recitation sections. That same year, a “Definitive Edition” of the lectures was released.