Richard P. Feynman to Francis Crick, March 7, 1978 / Francis Crick to Richard P. Feynman, March 10, 1978 / Linus Pauling to Richard P. Feynman, June 28, 1978 / Richard P. Feynman to Linus Pauling, July 7, 1978 by Richard P. Feynman narrated by Richard Poe / Francis Crick & Linus Pauling narrated by Johanna Parker