While competency-based principles have a history in vocational education, a growing number of typical high schools now are adopting competency-based programs. As is typical of any emerging field, a wide array of approaches is currently underway. Making Mastery Work describes the experiences of students, teachers, and administrators in a select, but varied, group of New England schools implementing competency education. In 2011-12, a team of researchers spent a year and a half examining 11 high schools that had started this work and wanted to expand their efforts. Dig in and explore the early state-of-the-art strategies documented here, with descriptions of each school’s experiences, and highlights of the key components, benefits, and challenges of the work already done and the work left to do.