Oscar Mendelsohn was the sixth child of Saul Mendelsohn, a storekeeper from Berlin, and his Brisbane born wife, Abigail, nee Rosensweig. He was educated at All Saints Grammar School, Melbourne, and Petersham Superior Public School, Sydney, before studying chemistry at Sydney Technical College. Mendelsohn subsequently worked as a chemist and teacher. He enlisted during World War One, but was discharged medically unfit and deployed in London as a chemist for the Chief Postal Censor's Department.
Returning to Melbourne in 1917, Mendelsohn continued the work begun in London, specialising in the chemistry of espionage. In 1919 he began a course in chemistry at the University of Melbourne, graduating with a BSc in 1923. Mendelsohn subsequently set up his own laboratory and O.A. Mendelsohn & Co.eventually expanded interstate. He became an expert in the food industry and on alcoholic beverages, advising state and federal governments, and later built a reputation as a forensic chemist and expert graphologist, publishing an account of his experiences in Suspected Documents and Outrageous Liars (1976). During World War II Mendelsohn served in the Royal Australian Air Force as a staff officer and chemical adviser at Air Force Headquarters, Melbourne.
Mendelsohn was a strong advocate of a civilised approach to eating and drinking in Australia. In later life, he wrote many books devoted to drinking, including a dictionary with 1187 synonyms for the word drunk. He was a regular reviewer and broadcaster and was the state president of the Fellowship of Australian Writers (1964-71), increasing Victoria's membership from fifty to five hundred. His enthusiasm for food, drink and the arts was manifested in the magazine Focus (1946-1948). Mendelsohn consolidated his social interests and intellectual pursuits in this journal. The inaugural editorial argued that 'There are few, if any, journals in Australia catering for intellectuals and presenting a point of view unbiased by party political prejudices or powerful sectional interests.' Attempting to fill this gap, Mendelsohn drew on a network of correspondents in Australia and overseas to write articles of general interest on politics, music, theatre, books and fine dining. Announcing plans for expansion in December 1946, Focus seemed to be growing in strength, but growing costs (particularly paper) must have caused financial difficulty during the following twelve months. Focus ceased production after the May issue of 1948.
During the 1960s, Mendelsohn's publications on Australian literature increased. In A Waltz With Matilda (1968), he contested Paterson's authorship of 'Waltzing Matilda'. He also edited several anthologies of poems and fiction during the 1970s.
(Source: Ray Marginson, 'Mendelsohn, Oscar Adolf (1896 - 1978)', Australian Dictionary of Biography, Volume 15, MUP, 2000, pp 349-450.)