Optoelectronics is a practical and self-contained graduate-level text on the subject. The authors include such topics as quantum mechanics of electron-photon interaction, quantization of the electro-magnetic field, semiconductor properties, quantum theory of heterostructures and nonlinear optics. They build on these concepts to describe the physics, properties and performances of light-emitting diodes, quantum well lasers, photodetectors, optical parametric oscillators and waveguides. The emphasis is on the unifying theoretical analogies of optoelectronics, such as equivalence of quantization in heterostructure wells and waveguide modes, entanglement of blackbody radiation and semiconductor statistics.