For centuries, camel caravans made epic journeys across the Sahara to reach the markets of the legendary city of Timbuktu, where they traded salt, gold, slaves, textiles - and books. By the mid-fifteenth century, Timbuktu had become a major centre of Islamic literary culture and scholarship, attracting scholars from as far away as the Arabian Peninsula. Students came from all over West Africa to learn at the feet of Timbuktu's masters of law, literature...