Adam criticizes Juliet's reading selection, saying that Ben wouldn't even read it in the bathroom.
In contrast, Ben previously intimated to Locke in "Maternity Leave" that he likes Stephen King, specifically preferring his books to those of Dostoyevsky. This may have been a bit of ironic humor on Ben's part, since the Book Club had been reading a Stephen King novel immediately before witnessing the plane crash, and Ben was interrogated by the Survivors 58 days later.
It's rather unusual that so many copies of the same book are available on the island. Although, in an effort to create various aspects of a society, it is possible that numerous editions of various publications were stocked on the island, it is very convinient that Juliet, a relative newcomer to the island, would be fortunate enough to have her favourite book present on the island. The copies of the book are also various editions with different sleeve artwork.
"So, I guess I'm out of the Book Club." ~ Ben to Juliet