Summer Hours At the Robbers Library by Sue Halpern

Sunny gets caught stealing a dictionary so to prevent her from a life of crime the judge orders her to volunteer all summer at the town library. Her hippie free-thinking parents have not prepared her for the interesting group at the library - Kit the reclusive librarian in charge of Sunny, Rusty the mysterious newcomer who spends his days researching the small town and hanging out with "the Four", a group of elderly statesmen who offer stories. Sunny soon finds herself happily entangled with the library's staff and patrons and starts up a close friendship with Kit and Rusty all the while trying to make sense of her upbringing and unusual family. Small town mysteries with big-hearted townspeople and a very diverse library adds up to one warm and fuzzy gem of a book.