"Fifty years ago today, on December 29, 2009, Richard P. Feynman gave an after-dinner talk in Pasadena at an annual post-Christmas meeting of the American Physical Society. Here is how Ed Regis describes the setting of the lecture in his rollicking book Nano: In the banquet room [at the Huntington-Sheraton hotel in Pasadena], a giddy mood prevails. Feynman, although not yet the celebrity physicist he'd soon become, was already famous among his peers not only for having coinvented quantum electrodynamics, for which he'd later share the Nobel Prize, but also for his ribald wit, his clownishness, and his practical jokes. He was a regular good-time guy, and his announced topic for tonight was "There's Plenty of Room at the Bottom" - whatever that meant. "He had the world of young physicists absolutely terrorized because nobody knew what that title meant," said physicist Donald Glaser. "Feynman didn't tell anybody and refused to discuss it, but the young physicists looked at the title 'There's Plenty of Room at the Bottom' and they th"