Good Behavior (Dortmunder, #6)

(6th Title in the Dortmunder series)
John Dortmunder's one of the slyest burglars going. But by God, he has bad luck! While fleeing the police during his latest caper, he falls through the roof of the Silent Sisterhood of St. Filumena -- and tumbles into the lap of trouble. It's an act of God, the sisters exclaim. Only the Creator himself could have sent this criminal just when they need him. Sure, they'll shelter him from the cops. But there's a price: He must help them to retrieve their youngest and newest member from her father's clutches. This promises to get sticky. Dear old dad hates the Sisterhood like the plague. And he happens to have an odd hobby: putting together mercenary armies. Why can't Dortmunder just catch a break?
"Westlake's most entertaining yet." (Publishers Weekly)