The Caspian Sea has attracted the attention of scientists, environmentalists, legal scholars and policymakers for a variety of reasons: scientists and policymakers are concerned about the sharp increase in the Caspian Sea level (2.5 m in 20 years). The rising waters have inundated coastal areas, including buildings, settlements, transportation infrastructure, and farmlands in each of the five countries that border the sea. br/ The Caspian Sea is also rich in resources such as fisheries and hydrocarbons. The caviar of the Caspian sturgeon is a highly valued export commodity, but the fishery is at risk from the rising sea level, pollution and oil spills. The oil reserves of the region are second in size only to the Persian Gulf. Only recently the Caspian was shared by two sovereign nations: the Soviet Union and the Islamic Republic of Iran. With the breakup of the USSR in 1991, three additional sovereign riparian States were added to the Caspian coastline: Azerbaijan, Kazakstan and Turkmenistan. International oil politics have become more complicated and more intense since the breakup, raising such international legal issues as the legal status of the sea (or is it a lake?) and its overland pipelines across different countries to sea ports with access to world markets. br/ Problems in other semi-enclosed bodies of water are also discussed, since such seas share similar environmental problems and potential solutions.