To produce the complex parts needed in many industries ranging from the aerospace and automotive industries to the medical field and to the energy sector, milling is either a key part of the manufacturing process or enables the tools for these industries to exist. Fundamentally, milling involves a cutting tool with multiple teeth that remove material in the form of chips on a milling machine having multiple axes. The milling processes have advanced significantly in terms of productivity and quality over time and naturally certain new issues have arisen. This book presents the current state of the art regarding these key issues while also proposing effective methodologies to optimize each part of this essential process. The preliminary chapters focus on the fundamental kinematics, mechanics and dynamics of milling operations followed by design optimization and motion control of milling machines. Spindle dynamics strongly affecting the performance of milling machines is the topic of the following chapter. The subsequent chapters focus on the milling of thin-walled parts, cutting tools with special geometries suppressing chatter vibrations and the thermal aspects of milling. Tool life has a direct effect on the productivity and cost of milling operations; thus, the next chapters are devoted to wear analysis and coatings for milling tools. Variations on the machine, tool and work conditions over time affect the performance in a milling operation. These changes can only be detected in real-time during operation using process monitoring which is the focus of the next chapter. In the last chapter, turn-milling offering higher productivity for large diameter parts and reduced tool wear in the machining of difficult-to-cut materials is presented as a growing technology of interest.