First came the Teds, then the Mods and the Rockers, then Hippies, Skinheads and Punks. But by the late ''70s, there was a new youth culture, one whose followers formed violent gangs, and were known as scallies,'' ''trendies'' and ''dressers'' until the name Casuals finally stuck. Definitively tracing the roots of this inner-city Liverpool movement through first-person interviews with the main ''faces'' of the gangs, Casuals explains how these hooligans evolved through the working-class fascination with sharp dressing to form bitter rivalries across England. With 16 pages of photos.''