This edition is accompanied by 3 Audio CDs and is suitable for both self-study and classroom use. Ideal for classroom use, this edition is also suitable for learners working on their own (at home or in self-access centres), as clearer rubrics for exercises have been included together with better overall navigation and a clear answer key. There is no separate Teacher's Book. This pack contains the second edition of 'Tree or Three?' and a set of 3 audio CDs.