Continuous and pulse sources of metal vapor for application in physics, chemistry, and technologies are described. The maximum temperature and vapor pressure are: T0≤2800 K, P0≤105 Pa. Source classification. The first group includes the sources involving the expansion of vapor into vacuum from the saturated state (or close to it). These sources are united by the common constructional feature, namely, the use of a single heater which limits experimental possibilities due to the difficulty of independent change of the characteristics of vapor expansion, i.e., pressure and temperature. The second group includes the sources in which vapor is superheated before expansion. These sources allow to handle the characteristics of vapor expanding into vacuum. The application of two-temperature sources in scientific research and in technologies allows one to control the metal gas dynamic flow, produce atomic, cluster beams, or vapor jets without microdroplet phase in it. The goal of the review is to demonstrate how to create a reliable metal vapor source with high intensity j≈1022–1023 atom/cm2 s and more with high optical density n≫1015 atom/cm2. © 1997 American Vacuum Society.