In 1967 James Dewey ("Jim") Watson passed his Honest Jim manuscript on to Pontecorvo for his comments and opinion. In 1968 The Double Helix: a personal account of the discovery of the structure of DNA was published. It is clear that Watson valued Pontecorvo's opinion on his famous text. Pontecorvo kept this manuscript safely in his personal papers and placed related presscuttings and correspondence within its pages over the years.
In the 1990s he sold other items in his extensive reprint collection to raise money for the University of Glasgow Department of Genetics but he refused to sell Watson's draft manuscript and the related correspondence. After Pontecorvo's death the family were keen that the manuscript be kept safely with the rest of Pontecorvo's papers.