This book is a generalist textbook; it is designed for anybody interested in heat transmission, including scholars, designers and students. Two criteria constitute the foundation of Annaratones books, including the present one. The first one consists of indispensable scientific rigor without theoretical exasperation. The inclusion in the book of some theoretical studies, even if admirable for their scientific rigor, would have strengthened the scientific foundation of this publication, yet without providing the reader with further applicable know-how. The second criterion is to deliver practical solution to operational problems. This criterion is fulfilled through equations based on scientific rigor, as well as a series of approximated equations, leading to convenient and practically acceptable solutions, and through diagrams and tables. When a practical case is close to a well defined theoretical solution, corrective factors are shown to offer simple and correct solutions to the problem.