Robert Lindsay Mackay was born on December 14, 1894, in Ottawa, Ontario, Canada. He was the son of Dr. Robert Alexander Mackay, a physician and professor, and Sarah Mackay. He had one sister, Mary Mackay, who became a nurse.
_His works include:_
- 1926: Advance-Australia: The Commonwealth and Foreign Policy
- 1941: The City of Ottawa: A Brief Social and Historical Description of the National Capital of Canada
- 1942: The Unrelenting Struggle: Some Notes on the International Conspiracy to Achieve World Power: Bolshevik and Nazi, Part 1
- 1950: Unrelenting Struggle: Some Notes on the International Conspiracy to Achieve World Power: Bolshevik and Nazi, Part 2
- 1954: The Honourable George Brown, His Life and Times: A Biography, the life and career of politician and newspaper editor George Brown (published in the U.S. as George Brown: Reformer, Radical and Responsible Statesman)
- 1959: Through Europe with Goethe: Being an English Rendering of His Travel Diary for the Years 1786-1788
- 1961: A History of the World: With Emphasis on the Significance of the British Empire, first published in Canada as Canada and the World
- 1963: The Real Mackay: In Search of a Canadian Tradition, a collection of essays on Canadian cultural history
- 1964: A Compact History of Canada, a one-volume history of Canada (published in the U.S. as A History of Canada)
- 1970: I Can: The Autobiography of Klaus Barbie, co-authored with Barbie from secret interviews with Barbie while he was in prison in La Paz, Bolivia
- 1972: The People of Canada, a three-volume encyclopedia on Canadian life, history, and culture
- 1973: The Case for the Canadian: A Self-Portrait of Canada, a sequel to _The People of Canada_