Contains correspondence with various prominent international scientists, chiefly on the subject of research questions or acknowledgements of books/publications received.

Correspondents include: Jean Brachet (concerning 'Lysenkoism'), Buzzati-Traverso, Julian Huxley, H.J Bhabha (concerning Indian students studying genetics in the UK), Theodosius Dobzhansky (concerning the arrival of Ukrainian scientist Boris Balinsky at the Institute of Animal Genetics in 1947). Also present is correspondence relating to the resuming of international relations with scientists after the Second World War, including a letter to Professor Crew (1947), signed by many members of the Genetics Society of Japan, including Takata, as well as Waddington's reports on his visit to Germany on behalf of the ARC in 1946 to collect information about German academic biology during the war.

Some letters are in French and German.