Stephen Leslie Case was born in 1933 and grew up in Hoylake on the Wirral (then Cheshire but now regarded as Merseyside).

He was educated first at Calday Grange Grammar School - as was his friend Dave Hall, (D. J. Hall) with whom he later wrote several books. Les then went on to University College Nottingham (now Nottingham University) where he successfully achieved a Bachelor of Arts Honours degree in English and History.

As a National Serviceman, Les served as a Sergeant with the Royal Army Educational Corps and then taught as Pensby Secondary Modern School for Boys in Cheshire. He then became Head of History at Stokesley Grammar Modern School in North Yorkshire and later Head of Humanities at Great Casterton Community College, Rutland, near Stamford.

With David J. Hall he co-authored "World History From 1783 to the Present Day" which was first published by Edward Arnold in 1967 with the Second Edition 1975.

Additionally, with his writing partner, D. J. Hall, 1971 saw the "Social and Economic History of Britain: 1700 to the Present Day" again published by Edward Arnold. The Second Edition came in 1977 and was re-named "Social and Economic History of Britain:1700-1976".

Two other products of this partnership are "A Visual History of the United States" in 1960 and "Modern European History through Maps and Diagrams" in 1970. Les died on Easter Day in 1981, so his last book in the Knowing series was co-authored with his wife, Christine (Farming through the Ages: S. L. & C. M. Case 1982).

His hobbies included gardening, boats, railways, railway modeling and music.