Electron Emission from Free-Electron Metals.- Work Function and Other Emission Measurements.- The Crystalline Solid as a Stack of Atomic Layers with Two-Dimensional Periodicity.- Electron States in a Semi-Infinite Metal.- Field Emission Spectroscopy of Metals.- Field Emission from Adsorbate-Covered Surfaces.- Field Emission Spectroscopy of Singly Adsorbed Atoms.- Field Emission from Semiconductor Surfaces.- Thermionic Emission Spectroscopy of Metals.- Secondary Electron Emission Spectroscopy.