Today’s Muslim world is in upheaval: legalists and mystics engage in intense debates, radical groups invoke Sharia, Muslim immigrants in the West face prejudice and discrimination, and Muslim feminists advocate new interpretations of the Koran. At the same time, Islam is mischaracterized as unitary and unchanging by people ranging from right-wing Western politicians claiming that Islam is incompatible with democracy to conservative Muslims dreaming of returning to the golden age of the prophet. Against this contentious backdrop, this book provides an essential and timely new history of the religion in all its astonishing richness and diversity as it has been practiced by Muslims around the world, from seventh-century Mecca to today. Most popular histories of Islam continue to repeat conventional pietistic accounts. In contrast, John Tolan draws on decades of new historical research that has transformed knowledge of the origins and development of the Muslim faith. He shows how the youngest of the three great monotheisms arose in close contact with Jewish, Christian, and other religious traditions in a mixture of cultures, including Arab, Greek, Persian, and Turkish; how Islam spread across an enormous territory encompassing hundreds of languages and cultures; how Muslims have forged widely different beliefs and practices over fourteen centuries; and how Islamic history provides crucial context for understanding contemporary debates in the Muslim world. At a time when much talk about Islam is filled with misunderstanding, stereotypes, and bias, this book provides a fresh and lucid portrait of the continuous and ongoing transformations of a religion of tremendous variety and complexity.