You can learn quite a bit about someone by reading their obituary.  As a prominent writer, Miss Mitchell's obituary appeared in The Times (London) on July 29, 1983.

Obituary - Miss Gladys Mitchell, Popular Crime Novelist (As printed in The Times -London, July 29, 1983)   Miss Gladys Maude Winifred Mitchell, whose detective stories have been popular for over five decades, has died at the age of 82.  She wrote as Gladys Mitchell, and also as Stephen Hockaby and Malcolm Torrie.   Born in Cowley, Oxfordshire on April 19, 1901, she was the daughter of James and Annie Mitchell.  Her father's family were Scots, and a Scottish influence is apparent in several of her novels.  Gladys Mitchell was educated at the Green School, Isleworth, Middlesex; then Goldsmith's and University Colleges, University of London.   Between 1921 and 1950 she taught at St. Paul's School, Brentford, St. Ann's Senior Girls' School, Ealing, and the Brentford Senior Girls' School, her subjects being English, history and games.   Retiring from this work in 1950, she became bored without the constant stimulus of teaching, even although she was then extremely busy with writing, and had been producing a book a year ever since 1929.  She accepted a position at the Matthew Arnold School, Staines and taught there from 1953 to 1961.  After then finally giving up teaching she lived at Corfe Mullen in Dorset for several years.  She remained unmarried.   Gladys Mitchell's first novel Speedy Death was published in 1929; it featured Beatrice Adela Lestrange Bradley, a witty, bizarre bu stylishly competent sleuth whose investigations were eventually to fill over sixty books.  Mrs. Bradley, later Dame Beatrice, a psychoanalyst, author and holder of honorary degrees from almost every university in the world, was the epitome of the professional woman.  Many of her rational and socially progressive views were similar to those of her originator, for whom at times she seemed a mouthpiece.  Some of the books, Death at the Opera, in 1934 and Laurels are Poison in 1942, for example, were set in the enforced closents of girls' school or college backgrounds which Gladys Mitchell knew so well and whose tension-generating potential she so skilfully exploited.   A survivor from the Golden Age of detective fiction (the 1920's and 1930's), she was an early member of the Detection Club whose active supporters included authors as celebrated as Dorothy Sayers, G.K. Chesterton and Agatha Christie.  She frequently satirized or reversed traditional patterns of the genre, succumbing to black humor, creating tongue-in-cheek mysteries and treading with extreme narrative confidence the hazardous paths between spoof and classic sleuthing fiction.  Many of her books were spiced by eccentric and colourful themes like transvestism, witchcraft or folklore esoterica, and her strong interest in ancient buildings and customs.  Her recreations included the study of architecture and writing poetry.   She wrote detective fiction with undiminished energy and adroidness well into the 1980's, and was a member of the Crime Writers' Association and the Society of Authors.     In 1976 Gladys Mitchell received the Crime Writers' Association Silver Dagger award.  As well as producing witty and incisive detective stories for adults she wrote several satisfying mystery books for juveniles.