An illuminating, scholarly history of the struggle over Estonia, Livonia and control of the Nordic-Baltic region by Sweden, Prussia, and Russia. Frost covers the heavily militarized period between the 16th-century takeover of the Baltic empires of the knights of the Teutonic order and the 18th century, when mighty Poland-Lithuania was devoured by its neighbors. Largely ignored today as a historical power, the flow of Polish-Lithuanian grain, timber, hemp and pitch through the Baltic provided vital raw materials for the European economy in the 16th and 17th centuries.  (BLT15, $51.60)