The correspondence between Crick and Waddington chiefly concerns a discussion of Waddington's theory of the epigenetic landscape, as well as the work of René Thom.

Much of Lord Halsbury's correspondence (1952-1957) are photocopies of the originals. There is a letter from Waddington's secretary, Anne Brown (dated 29 June 1976) to Lord Halsbury noting that she was returning the original correspondence to him having made copies to 'go to the Archives along with the rest of Wad's papers.' It appears that Halsbury sent Waddington his letters in 1970 along with a copy of his 'speculations on Protein Synthesis' which he wrote in 1951 for a discussion with Charles Dodds. It is unclear how Halsbury's papers came to be arranged with Waddington's correspondence with Crick.