Caltech's Division of Physics, Mathematics and Astronomy and The Feynman Lectures Website are pleased to present this online edition of
The Feynman Lectures on Physics

Feynman • Leighton • Sands


Now, anyone with internet access and a web browser can enjoy reading2 a high quality up-to-date copy of Feynman's legendary lectures.

This edition has been designed for ease of reading on devices of any size or shape; text, figures and equations can all be zoomed without degradation.3

Volume I

mainly mechanics, radiation, and heat

Volume II

mainly electromagnetism and matter

Volume III

quantum mechanics

Feynman's Tips on Physics

a problem-solving supplement to the feynman lectures on physics

Feynman's Messenger Lectures

full hd videos of 7 lectures feynman gave at cornell in 1964.

Lecture Recordings 1961‑64

117 flp lecture recordings4

Lecture Photos 1961‑64

3043 flp lecture photos5

Feynman's Notes

611 pages of flp lecture notes

Original Course Handouts 1961‑63

744 pages of flp student handouts6

Feynman Lectures Info

the original feynman lectures website

For comments or questions about this edition please contact The Feynman Lectures Website.

Richard Feynman talking with a teaching assistant after the lecture on The Dependence of Amplitudes on Time, Robert Leighton (left) and Matthew Sands (right) in background, April 29, 1963.

Photographs by Tom Harvey. Copyright © California Institute of Technology.

Contributions from many parties have enabled and benefitted the creation of the HTML edition of The Feynman Lectures on Physics. We wish to thank

  • Carver Mead, for his warm encouragement and generous financial support, without which this edition would have been impossible,

  • Thomas Kelleher and Basic Books, for their open-mindedness in allowing this edition to be published free of charge,

  • Adam Cochran, for tying up the many slippery loose ends that needed to come together in order for this edition to be realized,

  • Alan Rice for his steadfast enthusiasm for this project, and for rallying the support of Caltech's Division of Physics, Mathematics and Astronomy.

  1. Clicking the "Restore my view" link will take you back to where you last left off reading and listening in FLP chapters, or you can restore your view directly by loading a special URL, - bookmark it for convenience. The "Restore my view" link and URL will become active only after you've closed one of the chapters of this edition.
  2. However, we want to be clear that this edition is only free to read, look at and listen to online, and this posting does not transfer any right to download all or any portion of the book The Feynman Lectures on Physics, its photos or tape recordings, for any purpose.
  3. This HTML5-based edition features LaTeX equations rendered by MathJax JavaScript, and scalable vector graphic (SVG) figures. Your browser must support javascript and permit scripts from LocalStorage must be enabled. We recommend using a modern browser; some older browsers may not display this edition correctly. PNG figures (that degrade when scaled) may be served to browsers that do not support SVG. We do not support versions of Internet Explorer older than 9.0. For information about MathJax features and accessibility options, right-click on any display equation.
  4. The lecture recordings can also be played in their respective FLP chapters.
  5. Links to the photos also appear near the title of each FLP chapter.
  6. Updated in March 2022 with a new presentation featuring deep-zoomable images.