We had been teaching from the Feynman Lectures on Physics... using them as textbooks ever since Feynman had given the lectures, from '62 to '64.

...[T]hey had just gotten too hard.

It was great for the teachers; I loved teaching from his books. But for the students—if you didn’t already know physics, trying to learn physics from those books...

Seeing physics with fresh eyes all over again, it’s wonderful—that’s why every scientist in the world owns a set of these books...

[b]ut to learn it for the first time from those books is just impossible. You basically need to know physics, in order to appreciate them.