Thermodynamics involves a small number of postulates, but application of these to solve problems involves some subtle manipulation of partial differentials. Often, even when the solution has been obtained, the connection with physical reality can be lost. This book is complementary to standard thermodynamics textbooks. Its main purpose is to present extensive solutions and explanations to a series of thermodynamics problems. This will enable the student to learn by doing. The material covered includes the Laws of Thermodynamics, the principles and definitions of heat and free energy, and applications to heat engines, properties of materials and phase diagrams.