There were few basic aspects of computers and computation which intrigued Richard P. Feynman, and made the subject sufficiently interesting that he would spend time teaching it. Feynman himself did the lecture on quantum computation. Charles Bennett has already prepared the way by talking about reversible computation, and Norman Margolus on the billiard ball computer, so Feynman developed quantum computation in ways which made its connection to classical reversible computers obvious. His lecture was chiefly developing the idea that an entirely reversible quantum system, without damping processes, could perform universal computation. The insight that quantum computers were really different came only later, and to others, not to Feynman. Feynman only emphasized that the physical scale and speed of computers were not limited by the classical world, since conceptually they could be built of reversible components at the atomic level.