Kathryn Anne Ptacek was born on 12 September 1952 in Omaha, Nebraska, USA, but was raised in Albuquerque, New Mexico. She received her B. A. in Journalism, with a minor in history, from the University of New Mexico, Albuquerque, where she was graduated with distinction in 1974. While attending the university, she was a student of award-winning mystery writer Tony Hillerman and well-known YA writer Lois Duncan. Afterward, she worked briefly for a political party best left unnamed, was a telephone solicitor for the New Mexico Assn. of Retarded People, and spent two years as an advertising lay-out artist for a regional grocery warehouse co-op, and then worked for the University of New Mexico first as a secretary in the Dept. of Speech and Hearing, then for the University's Computing Center as their only technical writer and editor.
After the sale of her first novel, an historical romance, in July 1979, she quit to become a full-time novelist. As Les Simons, Kathryn Atwood, Anne Mayfield, Kathleen Maxwell, Kathryn Ptacek, and Kathryn Grant, she has written an historical fantasy series, numerous historical romances, and five horror novels. Her dark fantasy have won the Silver Medal and Gold Medal awards given by the West Coast Review of Books. She has also edited three anthologies, the critically acclaimed Women of Darkness and its companion Women of Darkness II (both Tor), and Women of the West (Doubleday). Editions of her books have appeared in England, Japan, Norway, Sweden and Germany. Her short stories have appeared in Greystone Bay, Doom City (Greystone Bay II), Fantasy Tales, the Post Mortem anthology, Pulphouse 5, The Horror Show, Freak Show (HWA anthology), A Confederacy of Horrors, Into The Fog, The Ultimate Witch, and Phobias. She is a member of Horror Writers Association, Mystery Writers of America, the International Women Writers Guild, and the Police Writers Club. She also prepares a market report for Hellnotes, is the editor of the Horror Writers Association's monthly newsletter, and publishes a market newsletter, The Gila Queen's Guide to Markets, which goes to writers and artists around the world.
On 1982, she married to dark fantasy novelist Charles L. Grant, who died in 2006. She shares a 116-year-old Victorian clapboard house with five cats in Newton, New Jersey. Her hobbies include gardening, jewelry making, and various needlework. She also has a large collection of gila monster memorabilia, and collects unusual teapots and cat whiskers.