This study was conducted in order to explore patterns of teachers' thinking and learning as they learn a new instructional approach. The theoretical framework is based on a model in which teachers: learn and implement a new practice; witness cognitive and attitudinal changes in students' learning outcomes; change their own beliefs and attitudes; and incorporate the new practice. Belief follows practice and observation rather than vice versa. The participants in the study were 21 teachers from 15 school administrative units in New Hampshire. Data sources were journal entries, questionnaires, videotapes of all teachers, and observations of nine teachers' classroom practice. Data indicated that most teachers reported alternating phases of frustration and increased surges of learning at identifiable stress points. All teachers adopted some routine practices of the innovation. Attributes of teachers' attitudes and knowledge changed from the beginning to the end of the institute. However, there was some reversion to an original state by the end of the following academic year. (Author/LL)