In ten sections, this book describes the principles and technology of Micro Mechanical Systems. Section one is a general introduction to the historical background and the parallels to microelectronics, reviewing the motivation for microsystems, and discussing microphysics and design and the evolution from microcomponents to microsystems. Section two covers the areas of photolithographic microfabrication, basic concepts of planar processing, materials, and processes. Section three looks at micromachining by machine tools, its history, basic principles and preparation methods. Section four discusses tribological aspects of microsystems. Section five covers fabrication, performance and examples of silicon microsensors. Section six looks at electric and magnetic micro-actuators for micro-robots. Section seven covers energy source and power supply methods. Section eight covers controlling principles and methods of micro mechanical systems and section nine gives examples of microsystems and micromachines. The final section discusses the future problems and outlook of micro mechanical systems.