Integrated quantum hybrid devices, built from classical dielectric nanostructures and individual quantum systems, promise to provide a scalable platform to study and exploit the laws of quantum physics. On the one hand, there are novel applications, such as efficient computation, secure communication, and measurements with unreached accuracy. On the other, hybrid devices might serve to explore the limits of our understanding of the physical world, that is, the formalism of quantum mechanics. Thus, optical quantum hybrid systems got into the focus of many researchers worldwide.This book gives a comprehensive yet lucid introduction to the exciting and fast-growing field of integrated quantum hybrid systems. It presents the theoretical and experimental fundamentals and then discusses several recent results and new proposals for future experiments. Illustrated throughout with excellent figures, the book also outlines the way for more complex devices to realize schemes to entangle distant quantum systems on-chip.