This book introduces the optical frequency-modulated continuous-wave (FMCW) interferometry - a new field of optics that is derived from radar. The study of optical FMCW interference not only updates our knowledge about the nature of light, but also creates an advanced technology for precision measurements. The principles, applications and signal processing of optical FMCW interference are systematically discussed. This book is intended for scientists and engineers in both academia and industry. It is especially suited to professionals who are working in the field of measurement instruments.