Section A, Biographical, presents significant material relating to McCrea's education and career, honours and awards. There are obituaries, interviews and biographical and autobiographical writings. The autobiographical writings consider some of his principal areas of research activity such as 'statistical physics', 'quantum physics', 'Dirac's Large Number hypothesis (LNh) and cosmology', 'solar system problems' and 'Relativity'. Of especial interest for the beginning of his career are the folders of notes made and the 37 notebooks kept by him as an undergraduate and research student at Trinity College Cambridge, 1923-1929, including the period at G�ngen in 1928-1929. Amongst the lecturers and topics represented are P.A.M. Dirac (Modern Quantum Mechanics), A.S. Eddington (Stellar Astronomy), R.H. Fowler (Thermodynamics and Kinetic Theory of Gases), D.R. Hartree (Physics of the Quantum Theory), H. Jeffreys (Operational Methods), J.E. Littlewood (Analysis Theory of Series) and F.J.M. Stratton (Stellar Physics). Also presented here are a series of 'personal' scrapbooks beginning with no. 3 '1960-1967 with a few earlier items' and continuing to the end of his life with no.17 '1993-1997'.
The scrapbooks document McCrea's career in photographs, newspaper cuttings, programmes of meetings, invitation cards, table plans, etc. A series of seven 'general' scrapbooks cover the period 1960-1997 and contain principally press-cuttings, especially obituaries. There is also a great deal of other personal memorabilia in the form of invitation cards, programmes, menu cards, seating plans and similar. Many relate to academic occasions, especially in the University of London or scientific occasions, for example at the Royal Society and the Royal Astronomical Society.
Section B, University Career, documents a succession of university positions at Edinburgh, Imperial College London, Queen's University Belfast, Royal Holloway University of London and University of Sussex. There is correspondence relating to his early career at Imperial and Belfast, 1934-1944, correspondence and papers relating to Royal Holloway including the Mathematics Department and continuing after his departure for Sussex, 1945-1984, while the Sussex material documents, amongst other matters, aspects of the work of the Astronomy Centre, 1966-1989. However, the largest group of university material relates to McCrea's teaching which is a particularly valuable record for the earlier part of his career at Edinburgh, Imperial and Belfast and continues at Royal Holloway. There is also teaching material for a number of his Visiting Professorships: University of California, Berkeley in 1956 and 1967 and Case Institute of Technology, Cleveland, Ohio in 1964. Also presented here are McCrea's notes on the university teaching of others (subsequent to his own undergraduate and postgraduate education), including E.T. Whittaker and C.G. Darwin at Edinburgh and J. Todd at Belfast.
Section C, Research, is predominantly the contents of McCrea's titled folders which may include manuscript working, drafts, correspondence and off-prints. The folders cover an extended period from 1928 to the 1980s and are presented in chronological order as far as possible. Folder topics include, amongst many others, relativity, 'Milne Theory', stellar models, interstellar molecules and continual creation. Folder titles may also indicate an association with the work of collaborators, for example 'Kermack - McCrea Problems' in the 1930s, and with that of research students, especially at Royal Holloway. Some of the folders contained drafts for identifiable publications and lectures and assignment amongst the sections of the catalogue was not straightforward.
Section D, Publications, presents a major chronological sequence of drafts and related material for McCrea's publications, covering the exceptionally long period of seventy years, 1928-1997. The non-availability of a reliable bibliography of McCrea's publications, especially for the period after 1970, meant that the designation of drafts as intended for publication was sometimes tentative. A separate sequence of reviews by McCrea covers the period 1949-1995. Publications correspondence documents McCrea in a number of advisory roles including journal editor. The largest group of papers relates to the Cambridge University Press, 1964-1991 where McCrea was an editor of the Press's General Relativity series and of the Cambridge Monographs on Mathematical Physics from the conception of the series in 1972. Correspondents include fellow editor D.W. Sciama. Of particular interest is a much shorter sequence of correspondence and papers relating to The Observatory Magazine. McCrea became an editor in 1935 and is referred to as a former editor in 1939. Correspondents include fellow editor R.v.d.R. Woolley and contributors S. Chandrasekhar, T.G. Cowling and E.A. Milne, and offering a paper 'as an outsider' J.B.S. Haldane.
Section E, Lectures, presents a major chronological sequence of drafts and related material for McCrea's public and invitation lectures, 1931-1993. The sequence documents the great variety of topics on which McCrea talked and the range of his audiences in Britain and overseas from Oslo in 1936 to Brioni, Croatia in 1990. Also presented here are a small group of lectures by other scientists including a notebook used for McCrea's notes of lectures by A.C. Aitkin, W.O. Kermack and E.T. Whittaker, possibly at an occasion at Queen's University Belfast while McCrea was professor there, and a duplicated typescript copy of a lecture on the meaning of wave mechanics given by Erwin Schr�ger in Dublin in 1952.
Section F, Societies and organisations, presents records of McCrea's association with twenty-five UK and international organisations including the British Association, Dublin Institute for Advanced Studies, a proposed UK Institute for Theoretical Astronomy, the International Astronomical Union (IAU), the Royal Astronomical Society (RAS), Royal Greenwich Observatory (RGO), Royal Society and the UK Science Research Council (SRC) / Science and Engineering Research Council (SERC). McCrea's British Association papers cover an extended period 1934-1983 including an early period from 1934 to the beginning of the Second World War when he was involved in various capacities with the work of the Committee of Section A (Mathematical and Physical Sciences). Although the Dublin Institute for Advanced Studies material covers a very short period 1940-1942, this represents the founding of the Institute. McCrea was a member of the Governing Board of the School of Theoretical Physics from 31 October 1940. There is significant documentation of the proposed UK Institute for Theoretical Astronomy, 1960-1966, possible locations being Cambridge (its eventual home) and Brighton. McCrea was a member (later Chairman) of the Subcommittee of the British National Committee for Astronomy which considered the proposed Institute. IAU papers principally relate to its general assemblies and symposia, 1955-1988, the 1935 Paris General Assembly being represented by historical reflections written by McCrea in 1988. McCrea's long association with the Royal Astronomical Society is documented by one of the largest components of the archive. There is a good record in correspondence and other papers of his Presidency, 1961-1963 and of the RAS Club, of which McCrea was President for many years. The most substantial group of RAS papers relates to the history of the Society, McCrea contributing a chapter on the 1930s in the second volume of its history (published 1987) covering the period, 1920-1980. McCrea also had a very long association with the Royal Greenwich Observatory which is extensively documented. There are records of the Admiralty Board of Visitors and its successor, the SRC RGO Committee and of the celebrations of the RGO Tercentenary (1675-1975) in which McCrea took a leading role. He prepared an historical review of the Observatory which was published by the HMSO in 1975, gave a number of papers on the RGO's history and wrote an article for the tercentenary exhibition catalogue. The most significant of his RGO papers, however, are probably those which relate to the decision of the SERC to move the RGO from Herstmonceux Castle in Sussex. McCrea was a very active campaigner against the move. He corresponded with politicians and colleagues and a number of colleagues copied their letters to him. He also wrote on a number of occasions to The Times which published an article by him on 23 April 1986. He attended a meeting of Fellows at the Royal Society, 23 May 1986, and a meeting convened by Patrick Moore, 6 June 1986, to express and to co-ordinate opinions that opposed the SERC's decision. Records of McCrea's Royal Society committee service illuminate developments in British astronomy and space science in the decades following the Second World War. There are also papers relating to two discussion meetings he helped organise: the origin and early evolution of the galaxies in 1979 and the constants of physics in 1983. Finally, McCrea's SRC / SERC material, 1966-1985, provides further documentation relating to British astronomy and space science and the future of the RGO.
Section G, Visits and conferences, provides a useful but incomplete record of McCrea's travel in the UK and overseas to attend all kinds of scientific meetings and conferences. The papers cover the period 1954-1989 and include his Visiting Professorships at University of California, Berkeley in 1956 and 1967, University of Cairo in 1973 and University of Otago, Dunedin, in 1979 and his visits as Royal Society Exchange Visitor to the USSR in 1960 and 1968 and to Egypt in 1981. He was a regular visitor to the University of Liege, Belgium to attend international astrophysical symposia and to the USA to attend Texas Symposia on relativistic astrophysics. Meetings held under IAU and Royal Society auspices are also to be found in Section F.
Section H, History of science and scientific biography, represents a major interest and commitment of McCrea. He wrote and lectured on historical and biographical aspects of areas of his scientific interest, especially associated with major anniversaries. He also wrote many obituaries and the Royal Society biographical memoirs of H.H. Plaskett and R.v.d.R. Woolley. There are particularly large accumulations of material relating to Einstein, R.H. Fowler, E.A. Milne, Plaskett, E. Schr�ger and Woolley. Records of his principal historical writing on the Royal Astronomical Society and the Royal Greenwich Observatory are to be found in Section F. Section J, Correspondence, is extensive and important and is presented in a number of alphabetical and chronological series suggested by McCrea's own arrangement. It covers the period 1942-1996. There is correspondence with colleagues and others relating to all aspects of his work including research, publications, lectures and visits and conferences. There are many examples of correspondence and papers from members of the public and amateur scientists on such topics as cosmology and relativity theory. Furthermore, there is significant correspondence in other parts of the archive, for example in association with his publications work and his professional affiliations with scientific societies and organisations. Taking the archive as a whole, there is correspondence of note with most of the major scientific figures in his areas of interest and the following list of principal correspondents is therefore highly selective: H. Bondi, S. Chandrasekhar, T.G. Cowling, H. Dingle, J.A. Jacobs, A.C.B. Lovell, R.A. Lyttleton, S.K. Runcorn, D.W. Sciama, J.L. Synge, R.J. Tayler, A. Uns- G.J. Whitrow, A.W. Wolfendale and R. v.d.R. Woolley.