Optoelectronics is a practical and self-contained graduate-level textbook on the subject, which will be of great value to both advanced engineering students and practising engineers. Sophisticated concepts are introduced in a practical and coherent way, including such topics as quantum mechanics of electron-photon interaction, quantisation of the electro-magnetic field, semiconductor properties, quantum theory of heterostructures and nonlinear optics. The book builds on these concepts to describe the physics, properties and performances of the main optoelectronic devices: light emitting diodes, quantum well lasers, photodetectors, optical parametric oscillators and waveguides. Emphasis is placed on the unifying theoretical analogies of optoelectronics, such as equivalence of quantisation in heterostructure wells and waveguide modes, entanglement of blackbody radiation and semiconductor statistics. The book concludes by presenting the latest devices, including vertical surface emitting lasers, quantum well infrared photodetectors, quantum cascade lasers and optical frequency converters.