This document presents case study profiles from a study that examined three aspects of educational time: (1) quantity of time in school; (2) quality of time in school; and (3) students' use of out-of-school time. Data were derived from case studies of 14 sites that experimented with different ways of allocating time as a cornerstone of efforts to improve the quality of teaching and learning. All of the schools in the sample serve a substantial number of disadvantaged students. In most of the schools, the time innovations represented important changes in the organization and structure of the schools. However, in some cases, the time innovations were part of the original design of the school. As a practical matter--as well as a finding about these schools--decisions about changing the quantity of time for teaching and learning followed decisions about other kinds of changes in schools. That is, in all but two cases, teachers and principals decided to change one or more elements of the core technologies (curriculum, instruction, and assessment) and concluded that changes in the allocation of time were necessary to support these changes in the quality of time. (AA)