HH: "Anthony Cheetham, both editor and friend, wrote that he needed stories on scientific themes that could be both used in a boy's science magazine, then later in an anthology ... I was interested and agreed, and decided to write a story about evolution. No shortage of material there. But the challenge was to organise it as a work of fiction, presented in an interesting yet simple manner for younger readers - and still write a story to capture the older reader when eventually the stories were anthologised ... Here it is, a work of fiction that perhaps tells you more about evolution than you care to know." Best of Harry Harrison).
Young Scientist, 1970
Science Against Man, edited by Anthony Cheetham. New York: Avon Books, December 1970, pbk, p.175-185.
Science Against Man, edited by Anthony Cheetham. London: Macdonald, 1971, hbk.
School and Society Through Science Fiction, edited by Joseph D. Olander and Martin H. Greenberg. New York: Rand McNally, 1974, hbk.
The Best of Harry Harrison, June 1976.
The Science Fictional Dinosaur, edited by Robert Silverberg, Charles G. Waugh and Martin H. Greenberg. New York: Avon, 1982, pbk.
as: "Trädet som Ständigt Förgrenar Sig" in Aschkelons Gator [The Best of Harry Harrison]. 1985. [Swedish].
50 in 50, July 2001.