A permanent issue in compulsory education is how to promote students' active working in the classroom. Even if group work is used as one type of working method in compulsory education as a means for committed learning and for social development, there seems to be a trend towards less time spent on collaboration tasks in favour of individual assignments in the classroom. This book presents compiled knowledge, based on previous research concerning co-operation in groups among students, or more specific, how to create and maintain well functioning group work in an educational context.