John Thomas Phillifent (10 November 1916 – 15 December 1976) was an English electrical engineer and author of science fiction and fantasy.
Most of his work was published as by Rackham, the main exceptions being three novels related to The Man from U.N.C.L.E.
series, his short stories published in the magazine Analog, and a number of late novels.
American author Frederik Pohl credits Phillifent with a comprehensive definition of science fiction that he dubs "Rackham's Law".
Pohl's own description of "the science-fiction method" (which Phillifent himself never troubled to define) is that "it consists in looking at the world around us, dissecting it into its component parts, throwing some of those parts away and replacing them with invented new ones - and then reassembling that new world and describing what might happen in it.