This comprehensive but concise textbook explains the variety of physical processes governing the formation, evolution and properties of planetary systems. Designed for readers with undergraduate backgrounds in physics, astronomy, and planetary science, it describes the key aspects in the field and the theory is carefully developed from first principles. It begins with a description of the main features of known planetary systems and of our current understanding of their formation, before moving on to the theory of non-gravitational forces involved in the evolution of planets and to the explanation of their magnetic fields. The book also covers the main aspects of planetary dynamics and concludes by introducing the fluid-dynamics concepts needed to illustrate the evolution of circumstellar disks and their interaction with planets.