There are 1.4 billion Muslims in the world—over a fifth of the world’s total population. Seventy percent of these Muslims live outside the Arab world, including Asia, Africa, Europe and North America. Despite its vastness, it’s a religion that remains a mystery to many in the West. Encompassed within Islam are Sunnis, Shiites, and Sufis, and within those broad divisions are still more layers that span from progressive to traditional and Islamist. This lecture draws upon Professor Asani’s highly popular core course at Harvard, “Understanding Islam,” and provides a framework to appreciate the diversity of Muslim thought and practice in different cultural and historical contexts.