He has authored multiple works, some of his notable works include:
- Robert Burns (1958)
- Scotland: A Cultural History (1972)
- Scottish Life and Society in the 18th Century (1979)
- William Dunbar: A Biography (1979)
- James Hogg: A Biography (1981)
- The People's Song: A Social History of Scottish Song from 1700-1950 (1984)