The Feynman Lectures on Physics, the 1964 textbook encapsulation of Richard Feynman's legendary lectures to Caltech undergrads in the early '60s, is online for the reading, Kottke notes—for free, and without having to navigate a PDF nightmare.

That's an obvious boon to college freshmen looking to slash their textbook budget for the semester. It's also a boon to pretty much anyone with a cursory interest in physics, quantum mechanics, and quantum electrodynamics.

Through his teaching, his work on the atomic bomb, and his involvement with the Rogers Commission, which investigated the Challenger explosion in the 1980s, Feynman has become one of the most recognized (and recognizable) physicists of the 20th century. As the text's new preface notes, his lectures live on after his death:

They have been studied worldwide by novices and mature physicists alike; they have been translated into at least a dozen languages with more than 1.5 millions copies printed in the English language alone. Perhaps no other set of physics books has had such wide impact, for so long.

Feynman, though, was not so self-congratulatory on the subject. In a preface to the text, he said that he was "pessimistic" that his lectures succeeded and wrote, "When I look at the way the majority of the students handled the problems on the examinations, I think that the system is a failure." His admirers have not quite agreed.

Photos of Feynman: Associated Press.