The story
Founded by Tom Doherty in 1980.1
Tor was founded by Tom Doherty in 1980, with Harriet McDougal and Jim Baen joining him from Ace as the editorial staff. (Baen and Doherty founded Baen Books three years later.) They were soon joined by Barbara Doherty and Katherine Pendill, who then composed the original startup team.
Tor is a word meaning a rocky pinnacle, as depicted in Tor's logo. Tor Books was sold to St. Martin's Press in 1987. Along with St. Martin's Press; Henry Holt; and Farrar, Straus and Giroux, it became part of the Holtzbrinck group, now part of Macmillan in the US.
In June 2019, Tor and other Macmillan imprints moved from the Flatiron Building, to larger offices in the Equitable Building.
From Wikipedia’s article on Tor Books, shared under CC BY-SA 4.0.4