Prepared as part of a series applying recent research in oral and written communication instruction to classroom practice, this booklet examines the language interaction that takes place between student and teacher and between student and student whenever a geniune dialogue about an important event or problem occurs. The first section of the booklet examines the connection between dialogue and thinking and looks at classroom dialogue as: (1) a means of allowing teachers to find out if students know right answers, and (2) a conversational partnership. The section also discusses written conversations as a way of thinking. The second section explores in detail how dialogue works, describes the concept of interactional scaffolding, and reviews the conditions for dialogue. The third section explores whether dialogue and social interaction help students to think differently, and the fourth suggests ways teachers can engage students in more thinking together. The booklet contains a number of examples of student work. (FL)