Well, something had to be decent in 2020...
Always hard to whittle these books down to even thirteen. Must give honorable mention points to all three Longmire mystery books (Another Man's Moccasins, The Dark Horse, Kindness Goes Unpunished) I devoured this year, plus my first read ever of Robert Heinlein's Tunnel in the Sky, with its POC protagonist who has been whitewashed on book covers for years, and to Linda Newbury, who managed to give me a decent sequel to Peyton's Flambards books.
The Mutual Admiration Society, Mo Moulton (ARC, Dorothy Sayers and her friends at Oxford and beyond)
The Olive Farm, Carol Drinkwater (book sale find, actor Drinkwater's memoir of the crumbling farm she and her partner bought in France)
The Letters of Dorothy L. Sayers, 1937-1943, From Novelist to Playwright (Volume 2), edited by Barbara Reynolds (book sale find, self-explanatory)
The Moor, William Atkins (nonfiction look at the various moors of England; they're not all the same)
The Narnian, Alan Jacobs (book sale find, story of C.S. Lewis as told by his writings)
America's Women: 400 Years of Dolls, Drudges, Helpmates, and Heroines, Gail Collins (book sale find, overview of the women who did not make it into the history books)
The Splendid and the Vile, Erik Larson (his newest about the Churchills during World War II)
The Annotated Black Beauty, Anna Sewell, introductions/annotations by Ellen B. Wells and Anne Grimshaw (a book find from a friend thinning out her library, expands knowledge of the novel and the treatment of Victorian animals)
Bryant & May: The Lonely Hour, Christopher Fowler (newest in Fowler's series; two elderly detectives look for a motive in unconnected murders)
A Furious Sky, Eric Jay Dolin (ARC, history of hurricanes in the "new world")
Something Wonderful: Rodgers and Hammerstein's Broadway Revolution, Todd S. Purdum (the team that was ahead of its time even thought they're thought by some to be "treacly" today)
This Old Man, Roger Angell (book sale find, essays about life, sports, and everything in between by "New Yorker" editor and stepson of E.B. White)
Olive Bright, Pigeoneer, Stephanie Graves (ARC, wartime mystery along similar lines as Poppy Redfern and the Midnight Murders, but, IMHO, better)