Beast in View, Margaret Millar, Random House, 1955, 249 pp
The Edgar winner for 1956 is an intersection of the mystery genre and Freudian ideas. One of the characters has a split personality, called schizophrenia in the 1950s but now called multiple personality disorder. The mystery comes into play because the reader does not know until the end which character is afflicted. According to the author's bio, she made an extensive study of psychiatry as part of her education.
The writing is mediocre and the story gets off to a slow start. But homosexuality also plays a part as well as wealth; a lot to bite off in 250 pages. This was only the third year that the Edgar was awarded and I suspect that Millar won on the strength of her topics rather than her writing, although the plot twist at the end was pretty effective.
(Beast in View is out of print, available in libraries and from used book sellers.)