Roberts did not hesitate to take on ambitious subjects, and in 1976 he published "The History of the World", regularly updated in later years and still in print today. "The Times Literary Supplement" described Roberts as "master of the broad brush-stroke", and in 1985 Roberts wrote and presented the thirteen-part BBC television series "The Triumph of the West", a series which painted a broad canvas but avoided simplistic solutions, encouraging the audience to think and reach its own conclusions. Later he served as historical advisor to the BBC series "People's Century".