Wave mechanics -- Atom-field interaction -- Stimulated emission and dipole oscillators -- Classical sustained oscillator -- Ammonia beam maser -- The state vector -- The density matrix -- Semiclassical laser theory -- Multimode operation -- Gas laser theory -- The ring laser -- The zeeman laser -- Coherent pulse propagation -- Quantum theory of radiation -- Coherent states -- Reservoir theory: density operator methods -- Quantum theory of the laser -- Quantum laser theory and measurement -- Reservoir theory: noise operator method -- Langevin theory of laser fluctuations -- Outlook