Charged-particle accelerators are the basic tools of high-energy physics, the science of fundamental properties of matter. Besides, a large number of synchrotron radiation sources are used world-wide for research and industrial purposes. Effective operation of modern accelerator facilities is almost impossible without precise and reliable diagnostics of particle beams. A review of instruments and methods of particle beam diagnostics in accelerators is given in this book. Physical principles of operation of beam diagnostic instruments of various types, such as contact probes, synchrotron...