P. D. James was an English novelist, best known for her mystery series featuring policeman and poet Adam Dalgliesh. Those I've read are all set in some kind of closed society -- an adaptation of the "closed room" mystery. She also has two mysteries starring Cordelia Gray, stand-alone novels, and non-fiction books.
She passed away in 2014, at age 94, still writing books and serving as a Life Peer in the House of Lords.
I've now read 12 of James's books. Unusual for me, all but one with my ears. The audiobook editions are particularly good and readily available from my library.
Those I have read are in red; those currently on my TBR shelf are in blue.
ADAM DALGLIESH MYSTERIES
Cover Her Face (1962) (country house)
A Mind to Murder (1963) (private mental hospital)
Unnatural Causes (1967) (writers' colony)
Shroud for a Nightingale (1971) (nursing school)
The Black Tower (1975) (reviewed here) (adult care home)
Death of an Expert Witness (1977) (forensic lab)
A Taste for Death (1986) (parish church)
Devices and Desires (1989) (community with a nuclear power plant)
Original Sin (1994) (publishing house)
A Certain Justice (1997) (inns of court)
Death in Holy Orders (2001)
The Murder Room (2003)
The Lighthouse (2005)
The Private Patient (2008)
CORDELIA GRAY MYSTERIES
An Unsuitable Job for a Woman (1972)
The Skull Beneath the Skin (1982)
Innocent Blood (1980)
The Children of Men (1992)
Death Comes to Pemberley (2011)
The Mistletoe Murder and Other Stories (2016)
The Maul and the Pear Tree: The Ratcliffe Highway Murders, 1811 (1971), with Thomas A. Critchley
Time to Be in Earnest: A Fragment of Autobiography (1999)
Talking About Detective Fiction (2009)