This book presents the resolution of thermal problems in various processes of working material such as molding, cutting, welding, or grinding. Two steps are presented for each type of application. The first is analytical, leading to general solutions that are well-adapted to the needs for the engineer at the time of the first dimensioning of the processes. This approach also provides tools for fast analysis with respect to the contribution of each transfer in a total assessment. The second approach is based on the finite element method. This method makes it possible to solve each problem with greater precision but at the price of an implementation longer and more expensive, thus providing the reader with the advantages and disadvantages of the different approaches, so that they can make a more informed decision when applying these methods. The inclusion of practical exercises and solutions also allows the reader to enrich their understanding by applying their knowledge to real-life cases.