The aim of this book is to provide a coherent and up-to-date discussion of the scientific work concerning the transformation toughening of ceramics. We hope the book is useful to scientists, engineers and students who are new to these materials. It is intended both as a source of learning and information to those who are new to these materials. It is intended both as a source of learning behaviour and microstructural relationships in transformation-toughened ceramics. While it has been our aim to present a book that is current as possible at the time of publication, the subject is still expanding in many areas; so our hope is that the reader will also gain an insight into the direction of future advances.