The river in question is the Arno, sweeping picturesquely through Florence, Italy. Introducing Sandro Cellini, a "defrocked" police detective who has turned to private detecting. He's approached by the widow of a recently-drowned man; the woman believes her husband didn't throw himself in the river. At the same time, Cellini investigates the disappearance of a British student from one of the many art schools that thrive in the city. The author's sure hand with the characters' emotions gives this tale a lot of depth, and her knowledge of the city (I may take the book next time I visit, get off the beaten path) is encyclopedic. This is a 5 for me...no, make it a 5+. My kind of stuff: suspenseful, probing, merciless, very sure-footed...I can hardly wait for more.