The fact that Venus has an atmosphere was discovered by M. V. Lomonosov in 1761. However, attempts to investigate its properties during the following two centuries were not sufficiently successful for construction of an adequate model. This situation has only recently been changed. The successful flights of the Soviet automatic interplanetary stations Venera 4, 5, and 6, the flight of the American space probe Mariner 5, and recent radio astronomical and radar investigations of Venus provide a great deal of important new information about this planet.