A mechanical oscillator coupled to the optical field in a cavity is a typical cavity optomechanical system. In our textbook, we prepare to introduce the quantum optical properties of optomechanical system, i.e. linear and nonlinear effects. Some quantum optical devices based on optomechanical system are also presented in the monograph, such as the Kerr modulator, quantum optical transistor, optomechanical mass sensor, and so on. But most importantly, we extend the idea of typical optomechanical system to coupled mechanical resonator system and demonstrate that the combined two-level structure and resonator system can serve as a generalized optomechanical system. The quantum optical properties, which exist in typical system, are also presented in the combined two-level structure and resonator system.Contents:IntroductionTheoretical Treatments in Generalized Optomechanical SystemsLight Propagation in Cavity Optomechanical SystemCavity Optomechanical System with Bose–Einstein CondensateThe Smallest Generalized Optomechanical System — A Single Quantum DotNanomechanical Resonator Coupled to a Single Quantum DotNanomechanical Resonator Coupled to a Hybrid NanostructureOptomechanical System with a Carbon Nanotube ResonatorA Circuit Cavity Electromechanical SystemA Hybrid Optomechanical System Based on Quantum Dot and DNA MoleculesReadership: Researchers whose interest lies in quantum optics or quantum physics and postgraduate students working on quantum optics or condensed matter physics.