The fonds consists mainly of correspondence files, folders, notebooks, personal and techncial photographs (black and white prints), describing Gill's working life from 1947 to 1975. The files and folders contain typescript and manuscript notes and working papers, annotated material, printed material, pamphlets, leaflets and press cuttings. Included are computer print outs of programme testing and Gill's Ph.D thesis entitled The Application of an Electronic Digital Computer to Problems in Mathematics and Physics, November 1952. Biographical and personal material (1947-1974) is also included in the fonds.

Series A mainly contains information about Professor Gill's working life and personal and technical photographs, including a significant document describing PILOT ACE computer problems (one typescript page). Very little documentary evidence of Gill's early career remains, but numerous letters throughout the collection amply testify to the friendly relationships he maintained with former colleagues at NPL, Cambridge and Ferranti Limited during the whole of his career. Gill was keenly interested in "computer policy" and wrote and lectured prolifically on this subject. His extensive correspondence and his collection of press cuttings, commercial and political reports and committee papers amongst others provide useful material for documenting the turbulent history of computer developments in Britain. Section G has been titled "Computer Policy" but Gill's deep conviction that computer technology was vitally important to Britain and his efforts to secure a strong position for it, are dominant themes throughout the collection and appear in every section. Section B contains many files of notes, working papers and correspondence relating to the four-colour problem on which Gill was working at the time of his death.

There is one box, labelled "Miscellaneous", which is uncatalogued and seems to deal with basic language collaboration with International Computers Limited and includes Annual Reports, 1965-1970.