Dorothy J. Heydt is a United States author of science fiction and fantasy. She lives on the U.S. West Coast and is an active participant in the Usenet newsgroups rec.arts.sf.written and rec.arts.sf.fandom, and in science fiction fandom in general. She is the originator of the "Eight Deadly Words" ("I don't care what happens to these people"), and other fan quotes. She was the originator and first editor of the Star Trek Concordance, an extensive resource guide first published in March 1969.
A linguist, she invented one of the first widely used Vulcanconlangs in 1967 for a Star Trekfan fiction series. Its words were picked up and used by other fan fiction authors such as Claire Gabriel. One term, ni var, meaning an art form in which two contrasting aspects of a subject are compared, is still used on Star Trek: Enterprise, as the name of a Vulcan ship.
While not one of the founding members of the Society for Creative Anachronism, she did participate in the early years and helped establish important elements of the ceremonies, such as the "Oath of Fealty" used in peerage ceremonies.