John Wyndham's science-fiction stories are memorable for the 'unthinkable' situations they postulate. His strength stems partly from the creation of tensions and choices that pose awkward problems for the reader as well as the characters—was Zellaby morally right to murder the children in The Midwich Cuckoos? Could his action even be termed 'murder'?—and partly from the nightmare quality of some of the pictures he presents: the silence of the suddenly-blinded city; the dreadful 'shrimping expeditions' of the 'seatanks' in The Kraken wakes.

Stowaway to Mars and The Secret People, first published in 1935, 16 years before The Day of the Triffids,… will disappoint anyone looking for the mixture as before—or, in this case, after. The title of Stowaway to Mars makes the first 50 pages almost redundant, and the virtually human Martians with their perhaps-sentient machines—this nettle is not firmly grasped—provide little leavening; while The Secret...