This book is basically about the theory explaining how metals and alloys behave and transform under various processing conditions. The processing changes the microstructures of the alloys and microstructures in turn control the properties of the materials. While writing this book care is taken to see that it is useful to the technologists working in metallurgical production facilities, R&D or academies. With strong fundamentals of phase transformation like thermodynamics and kinetics, the book offers insight into application oriented topics like solidification, heat treatment and thermo-mechanical processing. The topics like diffusionless transformation, spinodal decomposition and precipitation hardening find their due importance in the book. Chapters on shape memory alloys and ordering transformations are included to further the progressing knowledge in metallurgy. The book also contains materials not covered by traditional courses but required for solving a wide range of problems than just study of microstructure of metals and alloys. Although the book is written for undergraduate students, it is useful to postgraduate and research students as well. It is hoped that this book will induce readers to get interested in the subject and kindle to study and research further about phase transformation processes. Contents : 1. Introduction to Phase Transformation 2. Stability of Phases - Thermodynamics 3. Evolution of Phase Diagrams of Binary Systems 4. Phase Transformation Mechanism-Nucleation 5. Phase Transformation Kinetics- Diffusion 6. Growth Kinetics 7. Overall Transformation Kinetics 8. Solidification 9. Diffusional Transformation- Discontinuous Precipitation 10. Spinodal Decomposition 11. Diffusional Transformation: Continuous Precipitation 12. Precipitation Hardening in Al-Cu Alloys and Other Alloys 13. Precipitation Free Zones and Particle Coarsening 14. Plastic Deformation and Accompanying Relaxation Mechanisms 15. Diffusionless Transformations- Massive and Martensitic Transformation 16. Shape Memory Alloys 17. Ordering Transformation in Alloys References About Authors Author N.Ranganathan , a postgraduate in Engineering from Indian Institute of Science, Bangalore has wide experience in industry and also teaching experience in Indian technical universities SCSVMV University, Kanchipuram and MSAJCE, Anna University, Chennai. Professor.K.Rajendra Udupa has a PhD from Indian Institute of Science, Bangalore. With initial experience in the industry, he has more than three decades of teaching and research in National Institute of Technology, Surathkal, Mangalore.