This classroom-tested textbook is a modern primer on the rapidly developing field of quantum nano optics which investigates the optical properties of nanosized materials. The essentials of both classical and quantum optics are presented before embarking through a stimulating selection of further topics, such as various plasmonic phenomena, thermal effects, open quantum systems, and photon noise. Didactic and thorough in style, and requiring only basic knowledge of classical electrodynamics, the text provides all further physics background and additional mathematical and computational tools in a self-contained way. Numerous end-of-chapter exercises allow students to apply and test their understanding of the chapter topics and to refine their problem-solving techniques.