Gaining prominence as a seaport under the Ottomans in the mid-1500s, the city of Mocha on the Red Sea coast of Yemen pulsed with maritime commerce. Its very name became synonymous with Yemen's most important revenue-producing crop -- coffee. After the imams of the Qasimi dynasty ousted the Ottomans in 1635, Mocha's trade turned eastward toward the Indian Ocean and coastal India. Merchants and shipowners from Asian, African, and European shores...