Author: Stephen King (as Richard Bachman)
The blurb on Goodreads summarises the story much better than I can, so I'll give you that first:
"The fantasy of becoming trimmer--and happier-- turns into a nightmare of unrelenting terror for Billy Halleck who is 50 pounds overweight, sideswipes an old gypsy woman, and receives the maledictive sentence to get "thinner"."
The narrative begins somewhat slowly (not unusual for a King novel), but is quite engaging even before the action picks up. I was somewhat wary of the "gypsy curse" being a major focus of the story, but the psychological element is emphasized much more. While clearly a loving husband and father, Billy seems like a gluttonous fellow, as well as ignorant to the realities of life outside of his own bubble. It's hard not to feel resentment towards him initially, but the changes in his thinking throughout the story make him much more likable. His feelings of loneliness are legitimately sympathy-inducing. Much as I liked Billy by the end, I feel his old friend Ginelli stole the show when he showed up.
The climax is thrilling without being incredible, and the development of all important characters is complete. THINNER is a complex and rather dark tale with an ending that's so cheesy (and ironically comical) it actually works. I'd definitely recommend it to anyone looking for a good thriller.