Owen Letcher, mining engineer, journal editor, traveller and author, was the son of Thomas Letcher and his wife Mary Ann Davey. He studied at the Redruth School of Mines in Cornwall. At some time he was awarded a silver medal by the Miners' Association of Dover and Cornwall, and became an associate of the Institution of Mining and Metallurgy (London).
In 1907 Letcher undertook a journey in what is now Zambia. The next year he wrote a paper on "The auriferous banded ironstones and associated shists of South Africa" that was published in the Transactions of the Institute of Mining Engineering (1908). During 1909 he undertook a hunting expedition in Zambia and Malawi and kept a diary which is now in the library of the University of the Witwatersrand. In October 1910 he addressed the Rhodesia Scientific Association in Bulawayo on "The geographical distribution of big game in Northern Rhodesia". The paper was published in the association's Proceedings. The next year he published an article on "Mineral resources of central Africa" in the South African Mining and Engineering Journal (1911).
During World War I (1914-1918) Letcher served with the South African forces in South West Africa (now Namibia) and in East Africa, and later described the contribution of the South African forces in East Africa in his book, Cohort of the Tropics: a story of the Great War in central Africa (London, 1930).
For some years Letcher was the editor of the South African Mining and Engineering Journal. Among others he wrote articles for the journal on "Tin in South West Africa" (1921), "Zambesi minerals" (1922), and "Gold discoveries in the western Bushveld" (1922). He played a role in the creation of the Mining and Industrial Magazine of Southern Africa in 1925 and of the Rhodesian Mining Journal (Johannesburg) in 1927, serving briefly as editor of both journals. In later years he described himself as a consulting editor. On occasions he served as mining editor for the Rand Daily Mail and the Sunday Times. He was a member of the Chemical, Metallurgical and Mining Society of South Africa.
Letcher travelled widely, particularly in Asia and Africa. He wrote articles on his travels for the Geographical Journal, for example, "The Congo Zambesi watershed" (1923). He was elected a Fellow of the Royal Geographical Society (FRGS) and became a member of the South African Geographical Society in 1917, the year of its formation. That same year he delivered a lecture before the latter society on "North Eastern Rhodesia". He served on the society's council during 1919-1921.
During the years 1925 to 1930 he wrote about ten articles on mining and the mineral resources, particularly copper, of southern and central Africa for technical journals in the United States and the Rhodesian Mining Journal. In 1931 he was appointed to organise publicity for an international exhibition held in Elisabethville (now Lubumbashi) to showcase the produce of the Belgian Congo (now the Democratic Republic of the Congo). His experiences and views were also published in a number of books: Mines of Rhodesia: mining and settlers' guide (Johannesburg, 1910); Big game hunting in north-eastern Rhodesia (London, 1911); The bonds of Africa; impressions of travel and sport from Cape Town to Cairo, 1902-1912 (London, 1913); Letters from India (Johannesburg, 1924), describing a journey he undertook from Maputo along the east coast of Africa to the Seychelles and India; Africa unveiled (Johannesburg, 1931); South Central Africa (Johannesburg, 1932); When life was rusted through (Johannesburg, 1934); African mysteries: strange and true stories of the Congo and adjacent territories (London, 1935); and The gold mines of southern Africa; the history, technology and statistics of the gold industry... (Johannesburg, 1936, 580p), published to commemorate the 50th anniversary of the proclamation of the Witwatersrand.
In 1915 Letcher married Margaret W. Mair, with whom he had one son.