His book about the Carthaginian general, Hannibal: Enemy of Rome, is notable in its preparation: Cottrell traveled the ostensible path Hannibal took across the Alps into the Po River valley and incorporated his personal findings with his research in the book's narrative.
Leonard Cottrell was born 21 May 1913 at Tettenhall, Wolverhampton to William and Beatrice Cottrell(née Tootell). His father inspired an interest in history at the age of ten. At King Edward's Grammar School, Birmingham, Leonard was only interested in history and English, reading widely.
In the 1930s, Cottrell toured the English countryside on his motorcycle, visiting prehistoric stone circles, burial mounds of the Bronze Age, medieval and Renaissance monuments. On those journeys, he was often accompanied by Doris Swain, whom he later married, although the marriage was dissolved in 1962. After gaining experience writing articles on historical subjects for motoring magazines, he wrote his first documentary for the British Broadcasting Corporation (BBC) in 1937.
Leonard was rejected by the RAF during World War II, for medical reasons, but he joined the BBC in 1942 and they stationed him, in 1944, in the Mediterranean with the RAF as a war correspondent. His experiences as a war correspondent formed the basis of his book All Men are Neighbours (1947). He worked at the BBC until 1960, when he resigned and moved to a house overlooking the estuary of the River Kent in Westmoreland, Cumbria, where he stayed for the rest of his life, writing.
He was the editor of the Concise Encyclopaedia of Archaeology (1965).
He was married and divorced twice, to Doris Swain (in the 1930s, divorced 1962) and Diana Bonakis (married 1965 – divorced, 1968). He had had no children by either marriage.
Leonard Cottrell died on 6 October 1974.
- The Lost Pharaohs (1950)
- The Quest for Sumer (1952)
- The Bull of Minos: the discoveries of Schliemann and Evans (1953)
- Life Under The Pharaohs (1955)
- The Mountains of Pharaoh (1956)
- Seeing Roman Britain (1956)
- Lost Cities (1957)
- The Anvil of Civilisation (1957)
- The Great Invasion (1958)
- Wonders of the World (1959)
- Land of the Pharaohs (1960)
- Hannibal: Enemy of Rome (1961)
- The Tiger of Chʻin: The Dramatic Emergence of China as a Nation (1962)
- Land of the Two Rivers (1962)
- Realms of Gold: A Journey in Search of the Mycenaeans (1963)
- The Lion Gate: A Journey in Search of the Mycenaeans (1963)* Digs and diggers: a book of world archaeology (1964)
- The Secrets of Tutankhamen's Tomb (1964)
- Crete: Island of Mystery (1965)
- The Quest for Sumer (1965)
- The Land of Shinar (1965)
- Egypt (1965)
- A Guide to Roman Britain (1966)
- Great Leaders of Greece and Rome (1966)
- Lady of the Two Lands: Five Queens of Ancient Egypt (1967)
- The Warrior Pharaohs (1968)
- Madame Tussaud (1970)
- The Mystery of Minoan Civilization (1971)
- Reading the Past: The Story of Deciphering Ancient Languages (1971)
- Lost Civilizations (1974)
- All Men are Neighbours (1947)
- One Man's Journey (1955)
- Gale, Floyd C. (October 1961). "Galaxy's 5 Star Shelf". Galaxy Science Fiction. pp. 173–177.