Sam Youd distinguished himself as a writer of science fiction, first for the general reader and then for young adults, under the pseudonym John Christopher. Although he has several other pseudonyms--Hilary Ford, William Godfrey, Peter Graaf, Peter Nichols, Anthony Rye, and Stanley Winchester--the "John Christopher" name is on almost all of his science fiction. Productive, critically successful, and popular for more than half a century, he ranks among the top British science-fiction writers of the modern era. His short stories have appeared in the premier science-fiction venues, including Fantasy and Science Fiction, Playboy, and the best-of-the-year anthologies. His 1956 novel The Death of Grass (filmed in 1970) is a minor science-fiction classic. His young-adult science fiction is even more significant, especially the critically acclaimed Sword trilogy and the Tripods trilogy, on which the 1980s British Broadcasting Corporation (BBC) television series Tripods was based.

No significant writer of science fiction has...