The Caspian Sea is the unique natural feature, the world's largest landlocked water body. Historically the Caspian was one of the key zones where interests of such great powers as Russia, Britain and Persia clashed. And the reason is the oil - the "black gold" of the Caspian and also the natural riches of the sea - the sturgeons with their black caviar. With this encyclopedia an attempt was made to show the past and present of the sea where many geopolitical, economic, social and environmental issues are focused and that present interest to the Caspian and other countries of the world.The encyclopedia contains almost 1400 articles and terms providing descriptions of geographical features, cities, ports, main oil and gas fields, biological resources, international treaties, research institutions, activities of prominent scientists, researchers, travelers, military commanders, oil industrialists and traders who had relation to the Caspian Sea. In addition this book gives chronology of the most important events that became milestones in the history of the Caspian region development for more than 300 years.