The India trade in Oriental spices, pharmaceutical, dyeing and other materials was the backbone of medieval economy, especially in the Islamic world. A unique source of documentation is now available in 11th-12th century Geniza letters, written in Judeo-Arabic (Middle Arabic in Hebrew characters), by participants in this activity. The documents are presented in translation with an introduction and notes. They deal with economic history and material, social, and spiritual civilization. Besides illuminating the activities of the Jewish traders of the Indian Ocean and their families in the territories from the Far East to southern Arabia and Egypt, the letters contain valuable information on Jewish and Islamic culture, relations between Jews and Arabs, Mediterranean culture, and Judeo-Arabic.