One of the main fields of study of metallurgists, ceramists and other materials scientisits is the inter-relationships between structure and properties of materials. The subject of phase transformations plays a key role here. This book deals with the fundamental principles that governs the kinetics and the mechanism of solid state phase transformations and provides a good balance between the advanced concepts evolved in research and the class-room teaching. The emphasis being on principles, the presentation is generally applicable to all groups of materials.