Camino Island by John Gridham.

This is a fun page turner by Grisham at his best. A gang of thieves stage a daring heist from a secure vault at Princeton University. Bruce Cable owns a popular bookstore on Camino Island in Florida. He makes his real money, though, as a prominent dealer in rare books. He secretly dabbles in the black market of stolen books and manuscripts. He meets Mercer Mann, a young novelist with a severe case of writer’s block, who is approached by a mysterious woman with a generous offer of money if Mercer will go undercover and infiltrate Bruce Cable’s circle of literary friends, ideally getting close enough to him to learn his secrets.