Once in a while I get a hold of a book that is just an effortless joy to read. Midnight Riot, Ben Aaronovitch, is one of those books. Peter Grant is a young constable in London who gets his big break at the scene of a murder when he discovers he can see and speak to ghosts. He is reassigned to the enigmatic Detective Chief Inspector Thomas Nightingale, who investigates crimes of the uncanny kind. Nightingale gives him magic training, and when a wave of bizarre and gruesome killings starts, he must negotiate with ancient river gods and goddesses and outwit the spirits of long-dead murderers. It is fun and witty with vivid characters; best of all, it’s the first book in a series, so you can keep reading.