She started writing science fiction with the short story Rocket to Limbo in 1946. Her most creative period was during the 1950s, when she wrote such acclaimed stories as The Man Who Sold Rope to the Gnoles (1951), Brightness Falls from the Air (1951), An Egg a Month from All Over (1952), and Horrer Howce (1956). She largely stopped writing short stories after 1960. The Best of Margaret St. Clair (1985) is a representative sampler of her short fiction.
Apart from more than 100 short stories, St. Clair also wrote nine novels. Of interest beyond science fiction is her 1963 novel Sign of the Labrys, for its overt early use of Wicca elements in fiction. These elements may have derived from her reading of Robert Graves's book The White Goddess and of the writings of Gerald Gardner, with whom Margaret and her husband were put in touch by Raymond Buckland. It was Buckland who initiated the St Clairs into Gardnerian witchcraft. They were also influenced by reading the novels of Dion Fortune. [2]
When Margaret St. Clair's novel Sign of the Labrys came out in 1963, this indeed was news. SF definitely stood for science fiction then, although of course it was speculative too. It was the age of space opera starship troopers and slim-finned rockets pulling G's as they strained to leave planetary gravity. Technocrats ruled, while Beyond the perdurite windows, magnified in the crystalline clarity of the asteroid's synthetic atmosphere, loomed a row of the immense squat turret forts that guarded the Astrophon base--their mighty twenty-four-inch rifles, coupled to the Veronar autosight, covered with their theoretical range everything within Jupiter's orbit.
That is not Margaret St. Clair's writing; the first two quotations came from Jack Williamson's story Hindsight and the third from one of my old favorites, When the Bough Breaks, by Lewis Padgett. I found them by flipping through John W. Campbell Jr.'s 1952 anthology of stories previously published in Astounding Science Fiction magazine, one of the classic SF pulps. It was a masculine world of drawing boards and atomic pistols, and the only witches were female, perhaps interplanetary sorceresses like James H. Schmitz's The Witches of Karres.