This book argues that large American high schools have become obsolete and uses case studies of four new or restructured schools to show why smallness and distinctiveness are prerequisites for school reform. The large comprehensive high school developed as an economical means of providing a range of "tracks," from practical subjects for future factory workers to academic subjects for college-bound students. Today's knowledge economy requires that all students prepare for college and for technology-based work. An initiative of the Bill and Melinda Gates Foundation found that small school size contributed to improved teacher-student relationships and student engagement, more focused educational goals, and lowered teacher turnover and dropout rates. Four schools with such characteristics of educational excellence are described. The Julia Richmond Education Complex, a block-square "multiplex" in Manhattan, was transformed from an urban failure into a federation of six separate, successful schools under one roof. One of these--Urban Academy--serves many students who have failed at other schools, places students in leading roles in the classroom, and replaces standardized tests with long-term projects culminating in public presentations. The Metropolitan Regional Career and Technical Center (Providence, Rhode Island) ("The Met") uses student internships to encourage project-based learning and strong student-adult relationships. At Gary and Jerri-Ann Jacobs High Tech High, a San Diego charter school, students use technology to learn core subjects through independent and group projects. The Minnesota New Country School is a rural charter school run by the nation's first for-profit teacher cooperative. An appendix lists 30 small personalized high schools. A 30-entry bibliography lists related research. (SV)