This book explores understandings of knowledge creation that emerge from the experiences of three schools engaged in a process of whole-school renewal which focuses on the work of teachers. In each case, through collaborative effort, the teachers created new professional knowledge to guide their work. How this happened, what was achieved, the dynamics of the relationship between individual and group learning, and the subsequent impact on practice varied from case to case. The story of each school, constructed from the accounts of the teachers, is told to provide a basis for understanding knowledge creation in each context. Cross-case comparisons are then made to provide a more general understanding of knowledge creation processes and the factors which impact on the nature of the professional knowledge produced. The findings indicate that as creators of knowledge, teachers can re-image their work and give new meaning to teacher professionalism.