Trevanian was, according to his Wikipedia entry, so diverse a writer that some thought the name was "a collective pen name for a group of writers working together" (although to me his prose is always recognizable). His first two books, The Eiger Sanction and The Loo Sanction were delicious spoofs, over-the-top send-ups of the already over-the-top action/adventure/spy novel popularized by Ian Fleming with his Bond series. With his third novel, The Main he abruptly changed tone and color. The Main is a gritty, dark, realistic story about Jean-Luc LaPointe, a veteran cop widowed early and married now to his job. And then, in 1979, Shibumi, what many consider to be his crowning achievement, and one of the greatest international thrillers of all time.
He waited five years before publishing another novel. The Summer of Katya, while still recognizably Trevanian, turns in an entirely different direction, that of the psychological thriller, with a few gothic elements thrown in. The novel is narrated in 1938, from a perspective of twenty-four years after the summer in question. The narrator, Jean-Marc Montjean, is a young doctor working for a season in a clinic in a small Basque village a couple of hours from the village in which he grew up. He meets a beautiful young woman, Katya, a Parisienne living with her twin brother, and their father, a gentle and somewhat addled scholar of medieval history. Jean-Marc falls immediately in love with Katya, but, although he is allowed to visit the family daily for tea, he is not allowed to court her.
As the summer proceeds Jean-Marc is increasingly happy in his love for Katya, but also increasingly troubled by the family dynamic he observes when he goes to visit. Paul, the brother, is an arch snob who is exceedingly intelligent but seems to value nothing but his social status, the useless skills--such as kickboxing and target shooting--he has accumulated as a member of his class, and his small family. He exhibits nothing but contempt for the young doctor, despite the fact that Jean-Marc obviously makes his sister happy. As will happen in psychological thrillers--particularly those of an earlier era, to which Trevanian decidedly harks back--the twists to the story arrive quickly, one after the other, in the last seventy-five pages or so. They are, as is both the wont of Trevanian and of the genre, utterly over-the-top, nearly unbelievable, and deliciously satisfying.