"Base Pairs" by James Watson, an early draft (typescript, photocopied) of The Double Helix.
The text includes a Preface (from 10 Appian Way, Cambridge, Mass., August 1996), substantially the same as that of the published edition. The Foreword (here styled "Introduction") by Sir Lawrence Bragg is - minor stylistic modification aside - as subsequently published, with the notable exception that, following "He writes with Pepys-like frankness" ("Base Pairs" final paragraph, published text penultimate paragraph), the published version inserts the caveat: "Those who figure in the book must read it in a very forgiving spirit. One must remember that his book is not a history, but an autobiographical contribution to the history which will some day be written. As the author himself says, the book is a record of impressions rather than historical facts." For the revision of Bragg's text, see Bragg to Crick, 19 April, 1967 (PP/CRI/I/3/8/4).
Crick was critical of the title pun (which refers to the pairing DNA bases of adenine/thymine and cytosine/guanine): "I do not see why I should have a book published in which I am described as 'base'" (Crick to Watson, 27 September, 1966). The title did not impress Harvard University Press either and was rejected. For Crick's letter and other letters discussing the book, see PP/CRI/D/2/45, as well as PP/CRI/I/3/8/4.