Revision with unchanged content. A primary conflict regarding the identity of science education is the inherent competition between those who emphasize the science aspects of science education versus those who emphasize the education aspects of science education. This book describes a case of four science doctoral students collaborating with K-12 science teachers in a three-year partnership. The doctoral students divided their time between the K-12 science classroom and the science research laboratory. They learned and performed identities as both science educators and scientists as they moved back and forth between these two settings. In negotiating two worlds, the Fellows achieved heightened awareness of both the science and education cultures. At the same time, they experienced tensions as they attempted to negotiate their place in each culture. Illuminating and understanding such cultural issues is a crucial part of our understanding of our modern educational and scientific institutions. This book is addressed to university professors in both science and education departments, and to K-12 teachers in all fields.