Process planning plays a fundamental role within modern industrial facilities in that it is devoted to select the manufacturing processes and parameters and the sequences that are needed to convert a part from the initial to the final form. Evaluating the quality of a process plan from both a technological and an economic perspective becomes vital. Indeed, a valid process plan not only ensures the required quality of manufactured parts, but also reduces the production cost. The present chapter is aimed at presenting the essential concepts and the historical evolution of the process planning approaches, starting from a general point of view and then introducing the most important and recent real-world applications. In addition, it introduces the fundamental aspect regarding the interactions between process planning and production scheduling, pinpointing the strengths and weaknesses of the available proposed solutions. Doing so, it addresses students, researchers as well as practitioners.