An unsolicited manuscript about a literary-minded, independent-bookstore-dwelling rat that devours books has turned into an international hit—and a hefty paycheck—for Coffee House Press. Firmin, by 65-year-old debut author Sam Savage, was released by the Minneapolis-based nonprofit in 2006, and it's the book that keeps on giving. After garnering strong reviews and a spot as a finalist in that year's B&N Discover awards, Spanish publisher Seix Barral paid $100,000 for world rights to the title; fast forward to this year's Frankfurt, and Firmin, which was released in the U.K. a few weeks before the fair, still has Europeans buzzing.

Before Frankfurt, rights to the title had been sold by Seix Barral in more than 10 countries, including Italy, where Firmin was released this spring, selling nearly 300,000 copies. Coffee House, which printed a total of 15,000 trade paperback copies over three print runs, has ceased printing the book; Bantam, which bought paperback rights in 2007, will release Firmin as a Delta trade paperback in January.

Why all the fuss? Coffee House publisher Allan Kornblum thinks it's your classic publishing story—editors and readers simply fell in love with the book. According to a rep at Bantam, the acquiring editor there was tipped off about the book by a British editor friend after last year's London Book Fair, where Orion bought rights. (The book is being published in different formats depending on the country; in the U.K. it bowed in hardcover.) “The book speaks to that moment when a person discovers that reading opens up the world and, at the same time, isolates you from people who don't read,” Kornblum said.

Luckily for Coffee House, the ride with Firmin may continue. Savage—a Yale philosophy Ph.D. who, according to Kornblum, worked odd jobs for years and wrote “for himself” before a Coffee House intern stumbled on the Firmin manuscript—has another book, Cry of the Sloth, due from the indie in fall 2009. The book is about a struggling magazine editor going mad, and, Kornblum said, the protagonist is equal parts Don Quixote and Raskolnikov. This time, however, Coffee House will handle all rights sales.