The promise charter schools hold for public school innovation and reform lies in an unprecedented combination of freedom and accountability. Underwritten with public funds but run independently, charter schools are free from a range of state laws and district policies stipulating what and how they teach, where they can spend their money, and who they can hire and fire. In return, they are held strictly accountable for their academic and financial performance. To represent what such flexibility and accountability look like in practice, this guide, the third publication in the "Innovation in Education" series, provides a glimpse into the inner workings of eight American charter schools whose freedom to experiment is raising the level of student learning. Appended are: (1) Research Methodology; and (2) Resources. (Contains 9 notes and 10 figures.) [This publication was produced by the U.S. Department of Education's Office of Innovation and Improvement.]