"The Caspian Sea Encyclopedia" is the second one in the new series of encyclo- dias about the seas of the former Soviet Union published by Springer-Verlag. The ?rst volume - "The Aral Sea Encyclopedia" was published by Springer in 2009. The series will be continued by "The Black Sea Encyclopedia" in 2010. Today the Caspian Sea is known to readers thanks to its oil and gas resources, sturgeon and caviar, signi?cant sea-level variations, socio-economic and political problems. The Caucasus and Central Asia (http://eurodialogue. org/?les/fckeditor_?les/Caspian-s- map2. png) vii viii Introduction For more than 250 years the Caspian Sea was shared by two states: Russia (the Soviet Union) and Persia (Iran). After the disintegration of the USSR in 1992, the new independent states of Azerbaijan, Turkmenistan and Kazakhstan have radically changed the political and economic situation in the region. In addition to Russia and Iran, who had determined the situation on the Caspian for a long period, Azerbaijan, Turkmenistan and Kazakhstan are now interested parties, beginning a new stage in the historical development of the Caspian region. This increase in the number of the Caspian legal entities from two to ?ve has given rise to a whole tangle of geopolitical, economic, international legal, ethnic and environmental problems, each of which demands its own approach and settlement mechanism.