The benefits of a collaborative work setting--including such practices as mutual help, exchange of ideas, joint planning, and participative decision-making--have been consistently confirmed by studies of effective schools and successful businesses. However, teacher isolation remains the norm. Drawing on recent research and educators' firsthand experiences, this book explores the benefits of collaboration, describes various collaborative practices and programs already occurring in schools, and shows how these practices can be introduced using currently available resources. As chapter 1 shows, collaboration has no single model and can occur in formal programs or informally among a few faculty members. Collaboration cannot be imposed from above, but depends on educators' voluntary efforts at self-improvement through teamwork. Collaborative schools foster help-related exchange, harmonize teachers' professional autonomy and principals' managerial authority, and convert teacher accountability to a self-policing policy. The second chapter shows the costs of self-imposed, professionally sanctioned teacher isolation, as contrasted with the benefits of collaboration, including increased professional development opportunities, improved student cooperation, and a more collegial learning environment. The third chapter surveys current collaborative practices in such areas as school improvement, professional development, teacher evaluation, and school decision-making. Chapter 4 shows that developing new practices is itself a collaborative process involving all school professionals. Strategies are suggested for principals desiring to encourage collaboration and for comprehensive and modest undertakings. Policymakers' promotion of instructional leadership might help principals create a truly professional teaching environment. (84 references) (MLH)