The latest installment in Thomas's fascinating series unearthing the sordid underbelly of Britain (The Victorian Underworld) examines the postwar years, concluding his survey in the gritty 1970s. Between 1944 and 1945, he finds, violent crime almost doubled as army deserters and black marketeers struggled for control of the streets; by 1970, violent crime had only tripled. Not a shocking tabloid newspaper goes unread, not an Old Bailey transcript unperused, as Thomas tracks down the half-forgotten felons (Jack Spot, the Velvet Kid) who both terrorized and thrilled the country. Alongside the psychopathic killers (John Haigh, the "Acid Bath Murderer," who resembled Hollywood actor Ronald Colman), Thomas investigates the prostitution rings, the early days of drug dealing and the sharply dressed spivs who exported the fraud now known as three-card monte to the United States. On the other side, there's the creation of the Ghost Squad—undercover officers penetrating the underworld—and the rise of the "supergrass." In 1970, Bertie Smalls, a veteran of 15 armed robberies himself, put away 32 of his colleagues, who menacingly sang "We'll Meet Again" when he appeared in the witness box. It makes for wonderfully colorful history, told with all the relish of the true-crime aficionado in a very British, almost Dickensian kind of way. (Mar.)