Tabla de Contenidos: “…Electricity, magnetism, and waves -- Electrons and electron tubes -- Electromagnetic radiation and spectroscopy -- The atom and its electron world -- Photons-- packages of energy -- Atomic-energy ladders -- The first maser -- Traveling-wave ruby masers -- Ruby lasers and helium-neon lasers -- Semiconductor-junction lasers -- Waves and wave motions -- Electromagnetic-wave generators -- Maser uses and applications -- Laser uses and applications -- Simultaneous multivoice transmission -- The battle of the bandwidth -- Capsule history of the maser and laser.…”