It’s not a book, really, it’s a short story first published in the New Yorker. I haven’t read it yet, though I’ve saved it as a PDF. I had come across some buzz about the movie here and there, and Jason Kottke linked to the story at the New Yorker.
It’s directed by Ang Lee, whose films (at least the ones I’ve seen: Sense & Sensibility, Ride With the Devil, and Crouching Tiger, Hidden Dragon) seem to be about troubled or forbidden relationships, forbidden by custom, class, race, vocation. I have not seen The Ice Storm, which as I understand it covers similar ground in a Connecticut family, nor have I seen The Hulk, in which Jennifer Connelly and a large green man with anger issues have troubles. But that’s a digression.
Brokeback Mountain explores the forbidden relationship between two men with care and respect. I found it moving and genuine, and I greatly admire Heath Ledger’s performance. Recommended whole-heartedly.