J.M.S. Careless, the Canadian historian who wrote seminal works on George Brown, urban history and a changing Canada, has died. He was 90.

Careless died Monday at Toronto's Sunnybrook Hospital, according to his son, James Careless.

Careless won two Governor-General's Awards for his books of history — one for Brown of the Globe, a two-volume portrait of one of the Fathers of Confederation, and Canada: A Story of Challenge, which became a standard one-volume history of Canada.

He lectured at the University of Toronto from 1945 and became chairman of the history department in 1959.

Careless taught graduate and undergraduate courses in Canadian, political, ethnic, urban and intellectual history.

He was fond of reminding his students that nothing in history is inevitable until it happens, his son said.

He retired in 1984, but was named both senior research associate at Victoria College and Donald Creighton Lecturer at the University of Toronto in 1987.

Born James Maurice Stockford Careless on Feb. 17, 1919, in Toronto, he received a BA from the University of Toronto and a master's from Harvard before leaving his studies temporarily because of the Second World War.

During the war, Careless worked in Naval Service headquarters at Ottawa, then transferred to the Department of External Affairs, where he served as Canadian diplomatic officer aboard the prisoner-of-war exchange ship Gripsholm.

He completed his PhD at Harvard in 1950 while continuing to teach in Toronto.

One of the most respected historians of his generation, he wrote The Union of the Canadas in 1967, The Rise of Cities in 1978, Toronto to 1918: An Illustrated History in 1984 and Frontier to Metropolis in 1989.

His writing about Canadian history also turned up in both scholarly and popular journals.

Careless was an adviser to the National Film Board's historical series from 1961 to 1966 and contributed to radio and television projects for the CBC and TVOntario.

He was also active in public service and in preserving historical sites.

Careless served as president of the Ontario Historical Society in 1959, vice-chairman of the provincial Archaeological and Historic Sites Board and co-editor of the Canadian Historical Review.

He is a recipient of the Order of Ontario and the Order of Canada.

He is survived by his wife Elizabeth Isobel Robinson, five children and 10 grandchildren.