became the title of a successful play: For a review of the play Photograph 51, see, eg, http://theater.nytimes.com/2010/11/06/theater/06photograph.html.

“It might be good for you”: Letter from Linus Pauling to Peter Pauling on March 27, 1953. At http://osulibrary.orst.edu/specialcollections/coll/pauling/dna/corr/sci9.001.33-lp-peterpauling-19530327.html.

“Although it is only two months”: Pauling and Bragg 1953.

“Failure hovers uncomfortably close”: Watson 2000.

The new view that emerges: See, eg, Reich et al. 2011, and interesting discussions on the blog page of paleoanthropologist John Hawks, john hawks weblog.