The Good Shepherd
C. S. Forester
There's a long and honorable tradition of destroyer-vs.-submarine novels. (One of the all-time great Star Trek episodes, "Balance of Terror," is for all intents and purposes the same thing.) The Good Shepherd is one of the best–and most realistic. It's written in dry, clipped, matter-of-fact prose . . . and it's hard to put down. It works as a war story, but it also works as a subtle character study.
I read The Good Shepherd in high school. I was pleased to discover that I like it just as much today.