This book evolved from contributions of various experts who presented their thoughts developed over many years of teaching and research. The idea of this book is to present the various research domains of heat transfer in which work is ongoing. The work includes heat transfer augmentation techniques, MHD, fuel cells, solar systems, nano fluids, etc. This book is intended for research students, PG students and industry professionals. Heat transfer is a very broad subject so the selection of chapters is made in accordance with the need to cover the majority of topics dealt with in heat transfer and focus is placed on areas where the availability of literature is limited compared to other topics. We welcome feedback from readers that will improve the subsequent edition of this book.