This qualitative research describes unique features of seven exemplary science teachers' professional development activities. Description of excellence in effective teachers' professional development efforts will provide some insights into required inservice initiatives and support systems for teachers' professional learning. Exemplary science teachers' professional development activities can be classified into four types: (1) practicing classroom supervision, (2) participating in voluntary communities of teachers, (3) playing instructional leader roles in teacher training programs, and (4) continuing one's studies at a graduate school. One of the common features of these exemplary teachers was that they can both articulate what makes teachers professionals and practice in accordance with their perspectives. These exemplary teachers not only improved their own classroom practices, but also participated actively in various professional communities to share their practical knowledge with their colleagues. The teachers have formed special-interest groups to investigate better ways of science teaching. They also took an active role in teachers' in-service education. Teachers' quality practices lie at the heart of classroom change. However, it's important to remember that there must be a support system that sustains and encourages teachers' initiatives. The implications for the support system to encourage teachers' professional development efforts are discussed.

• Kwak, Young-Sun(orea Institute of Curriculum & Evaluation)