The Prehistoric Age investigates the origins of life through the examination of fossilized remains and the depiction of extinct creatures.

The book is presented as an exploration of prehistoric life, drawing on the expertise of the Department of Palaeontology at the British Museum. Its scope covers a broad spectrum of extinct organisms, suggesting a comprehensive overview of the subject. The focus on fossil evidence and the probable origin of life indicates a scientific and educational approach. The inclusion of early mammals and man suggests a narrative that traces evolutionary lines towards modern life.