This book is aimed at graduate students as well as scholars intending to take up multiphase flow/heat transfer as a field of research. The field of phase change from vapour to liquid and vice versa is complex and still developing even after a century of research. This often makes a beginner in the area overwhelmed. The purpose of this book is to introduce the subject in a simple and scientific way. The physics of the processes in boiling, condensation and cavitation are stressed upon in the text. The book also introduces some unique aspects such as phase change equipment and newer developments such as numerical modelling as well as mini and microchannel phase change. Contents 1. Introduction to Two Phase Flow—Flow Patterns and Maps 2. Two Phase Flow—Pressure Drop and Flow Friction 3. Thermodynamics of Phase Change 4. Nucleation and Bubble Dynamics 5. Cavitation 6 Types of Boiling—The Pool Boiling Curve 7. Heat Transfer Mechanisms and Correlations in Nucleate Pool Boiling 8. Pool Boiling Crisis, Critical Heat Flux and Film Boiling 9. Flow Boiling Heat Transfer 10. Flow Boiling Crisis and Post Dryout Heat Transfer 11. Condensation: Nusselt Theory and External Condensation 12. In-Tube and Dropwise Condensation 13. Boiling and Condensation of Mixtures 14. Numerical Modelling of Boiling 15. Equipment for Boiling, Evaporation and Condensation 16. Boiling in Mini and Micro Channels