Anita Shreve’s latest book, “Stella Bain,” is a slender novel with a large and complex subject. It begins in London, in 1916, when Lily Bridge, a kind and prosperous matron married to a distinguished cranial surgeon, comes upon a woman in great distress. She is ill, penniless and dressed in a uniform of the British medical service. She has made her way, at great cost to herself, from the trenches of World War I in France. She is convinced that she must get to the British Admiralty, but she can’t remember why. Indeed, she can’t remember anything about herself. But it’s plain from her diction and demeanor that she is a woman of education and breeding, and also an American. On impulse, Lily asks the woman to come into her home. She and the doctor will care for her for some months. At the beginning, all the trio has to solve the mystery of the woman’s origins is a name that has come to her at random: Stella Bain.

Stella is suffering from shell shock, or what we would now call PTSD. At this time, the ailment was scarcely known. Stella and Dr. Bridge embark on a course of the “talking cure,” an innovative treatment in 1916. It turns out that Stella has a back story that’s uneven and strangely specific, with dangling characters and obscure motives.

Dr. Bridge repeatedly takes Stella to the Admiralty, where they sit on benches and wait to recognize someone or to be recognized. At their fifth visit, she is called by her real name, which slams her past back into memory: She is not Stella Bain but Etna Bliss Van Tassel, the wife of a second-rate American academic caught up in a nefarious plot.

Etna, we learn, had married Van Tassel for the reason so many young women of that day made that decision: to get out of the house she was living in. She never loved him, and he was a bad sport about it. Worse, Van Tassel entangled their young daughter in a scheme that eventually sent Etna to Europe, where she became one of the Great War’s many casualties.

Shreve, the bestselling author of more than a dozen novels, is meticulous in performing the tasks she has set herself. She examines what shell shock meant in the early 20th century and how women’s injuries were ignored or misinterpreted. And she provides a fascinating portrayal of early Freudian psychiatric treatment and early plastic surgery. (One character, whose face has been blown off, wears a tin mask with enameled features carefully painted on.) She falters only when looking at the issue of independence for women: We are asked to believe that Etna makes her very good living by doing medical drawings, but that occupation takes place off stage and pays for any number of transatlantic voyages.

(Little, Brown)

But mainly, Shreve creates a good-sized canvas of intelligent, well-meaning, well-educated human beings trying to adjust their longings to the rough wishes of the larger world at war.

See regularly reviews books for The Washington Post.

Stella Bain

By Anita Shreve

Little, Brown. 265 pp. $28