In Genetic Takeover (Cambridge: Cambridge University Press, 1982), Cairns-Smith argued, in full technical detail, that life was originally based on self-replicating inorganic crystals. Seven Clues to the Origin of Life, originally published in 1985, presents his hypothesis at the popular level, engagingly written with ubiquitous references to the methodology of Sherlock Holmes. Seven Clues to the Origin of Life "is a summary of the best evolutionary thinking as applied to the origins of life in which the important issues are addressed pertinently, economically, and with a happy recourse to creative analogies," wrote the reviewer for Nature.