Although teachers across the country are creating new knowledge in their classrooms, researchers preoccupation with large-scale assessment policies leave out any vital discussion of teachers efforts, experience, and insights. Kathe Jervis corrects that omission by presenting three case studies of teachers implementing authentic assessment. Her thoughtful descriptions of classrooms in three schools reveal how teachers address policy issues as they put portfolios into practice, as well as how they respond to the particular needs of their students and their own values.