He was raised in a diplomatic family and spent some of his early years in South Africa. Unable to return home when Yugoslavia was invaded by Nazi Germany 1941, the family settled in Great Britain. He studied at Cambridge and London before proceeding to Oxford University, where he received his doctorate in 1958, before moving to Canada. After teaching for a few years in Manitoba, he joined the UBC faculty in 1963 – initially as a member of the Department of Political Science and then from 1969 on as a member of the Department of History, in which he served until his retirement in 1991.
He was a prolific historian of political movements in Europe and North America from the late nineteenth century to the present and read a wide range of European languages. While still a student, he co-authored with George Woodcock a study of one of the founders of anarchism: The Anarchist Prince: A Biographical Study of Peter Kropotkin (London, 1950) and a study of a Russian sect: The Doukhobors. On his own, he published History of the Communist Party of Yugoslavia, The Communist Party in Canada: A History, and Socialism in Canada: A Study of the CCF-NDP in Federal and Provincial Politics. He also wrote many articles, entries in reference works and document collection.