A quantum dot with an excess conduction band electron constitutes a new paradigm for solid-state quantum optics. When an external magnetic field is applied along the growth direction, the lowest-lying optical excitations could be modeled as a pair of weakly coupled two-level systems; this system could be used for spin-photon entanglement and optical read-out of the electron spin. If the external field is perpendicular to the growth direction, the two low-energy spin states could be coupled via Raman transitions, allowing for efficient spin cooling and coherent optical spin rotation. The optical physics of a singly charged quantum dot is enriched by the presence of coupling to nuclear and electron spin reservoirs.