As a substitute teacher in the schools of San Francisco and South San Francisco, Tom Gallagher sees kids on their worst behavior five days a week - that's when business is good. Once a member of the Massachusetts House of Representatives, Gallagher currently holds the line against academic entropy in everything from pre-Kindergarten through 12th Grade, from Physics to Phys Ed. The fundamental stance of Sub: My Years Underground in America's Schools is wry - it dares raise questions like why the guy who invented middle schools was never prosecuted for crimes against humanity. At the same time, Gallagher finds much of the current national debate on education misplaced - the system works just fine for some, but for others - particularly in much of urban black America - where they may be the only lifeline available, schools are asked to solve problems in children's lives that are far beyond their scope.