Mr Matson has described his career and the background to his collection as follows:

He was born in Sipson, Middlesex, on 5 Apr 1915. After leaving Southall Grammar School in 1933 with a Higher Schools Certificate, he trained and practised as an Environmental Health Officer until Dec 1939. He served in the Army until Jul 1944 and was then appointed Environmental Health Officer in the Kenya Medical Department.

He was stationed at Nakuru for two months and in Kisii for four years before being posted, in 1949, to Kapsabet, where he remained until Aug 1963. He retired to Seaford in Sussex and devoted time to writing Nandi Resistance to British Rule and to East African studies.

At a meeting of the Nandi District Council in 1950, Senior Chief Elijah arap Chepkwony asked that the history of the Nandi be recorded while there were still elders alive who remembered the long struggle that preceded Nandi acceptance of British rule. Matson volunteered to collect information from official records and published works. This research developed into recording elders' reminiscences as a basis for a history of the tribe. To honour his commitment to the Nandi, he spent local leave in the Nairobi, Mombasa, and Entebbe Archives, district offices, etc., and overseas leave in the Public Record Office, British Museum, the libraries at the Colonial Office and Royal Commonwealth Society, on missions, etc.

As there were no similar bodies in Kenya at the time, and few outlets for historical contributions, Matson joined the Uganda and Tanganyika Societies and submitted several articles to the Uganda Journal and Tanganyika Notes and Records. As a result of his membership of the Uganda Society, he was honoured with the friendship of H.B. Thomas, which enabled him to extend the scope and depth of his interests. Matson became a founder member of the Kenya History Society. However, after a most promising start, the society did not survive for long.

In the mid-1950s, East African studies, which had been left almost entirely to enthusiastic 'amateurs' (such as C.W. Hobley, H.E. Lambert, Elspeth Huxley, Edward Rodwell, M.F. Hill, Sir John Gray, and H.B. Thomas) were enlivened by the arrival of several British, Commonwealth, and American scholars, many of whom went on to become professors in different parts of the world. Their supervisors, notably Margery Perham and George Bennett, naturally put them in touch with local workers, and there was a welcome quickening of interest, one of the manifestations of which was a search for records, personal accounts, etc. This was formalised in the Colonial Records Project, which Margery Perham sponsored at Rhodes House. In this and other fields, a large part was played by the scholars attached to Makerere and, later, the University Colleges at Nairobi and Dar es Salaam.

In Jan 1958, Matson submitted an historical article to Kenya Weekly News, which developed, under Mervyn Hill's guidance, into a series of 39 essays, which appeared in 51 issues up to Dec 1963. These articles, which contained much archival material that had not been used before, generated a great deal of interest and correspondence, and the files on them were continued after publication. Biographical entries were collected for a number of years, which were eventually incorporated into the Dictionary of East African Biography Project, which had been started by Sir John Gray, H.B. Thomas, and Donald Simpson, the Royal Commonwealth Society Librarian. Information was sought from various authorities, and a draft mimeographed list circulated, from which an edited and extended list has recently been prepared, hopefully for publication. In Kenya, Matson was too busy to undertake the lengthy, consecutive periods of study necessary for a book, and thus had to restrict his activities to articles for various learned journals. An exception was an abridged, edited, and largely rewritten version of Ian Orchardson's The Kipsigis, which Charles Richards, then of the East African Literature Bureau, encouraged him to prepare.

After retiring, in addition to completing a book, Matson paid fortnightly visits to H.B. Thomas and acted as his (and Sir John Gray's) literary executor. He was a member, and briefly, Chairman, of the Library Committee of the Royal Commonwealth Society, took over from H.B. Thomas as UK representative of the Uganda Society, attended seminars at the Institute of Commonwealth Studies London, Sussex University, etc., continued with archival research, kept in touch through correspondence and the visits of scholars and students, including some from Africa, many of whom used his papers for their research, commented on draft books, theses, articles, etc., and answered numerous queries on a wide variety of subjects. Before falling ill, he was working on the completion of the Nandi resistance saga and on an edited version of the letters of Francis Hall from Kikuyu, 1892 to 1901. Other subjects for which material for a book had been assembled included the Uganda Road, ships on Lake Victoria, the Freelanders, and the introduction of wireless to the East African region. He died in 1987.