 Nicholson authored numerous histories of Canada's military.He is best known for his 1962 book "Canadian Expeditionary Force, 1914-1919", the only official history of Canada's participation in World War I.

Gerald William Lingen Nicholson was born on 6 January 1902 in Weston-super-Mare, Somerset, to Arthur Thomas Nicholson and Caroline Dora Middleton (1860-1932).He had a twin brother, Arthur Edmund Delabere “Ted” Nicholson (1902-1971), as well as an older brother Harry Sholto Nicholson (1893-1975).