The urge to understand tropical meteorology has been driven by a variety of forces that include the devastation caused by tropical cyclones, demands by military operations (for example, World War II, the Marshall Islands weapons tests, and the conflict in southeast Asia), and the belief of influential mid-latitude meteorologists that the tropics may hold the key to successful forecasts of global weather patterns and climate change. As correctly forecast in the Preface to the first (1971) edition, "Forecasters' Guide to Tropical Meteorology," by Major Gary D. Atkinson, AWS TR 240 was used not only to train Air Weather Service meteorologists, but also as a text for university courses. It was even translated into Chinese. Technological advances in the last 20 years, especially in satellite-based observations, have not seriously affected views expressed in the first edition, but have allowed them to be expanded and refined. Both climatology and synoptic meteorology have benefitted, while many hitherto obscure parts of the tropics have been exposed to the global eye. This edition was prepared under contract with the Department of Meteorology, University of Hawaii. Satellite data and wide-ranging research now allow the tropics to be treated more evenly and extensively than before. Sections dealing with Africa, the Americas, and south and southwest Asia have been expanded. Satellite picture illustrate tropical systems and processes.