The diversity of cultural and religious practices of Islam is reflected by the geographic expanse of the Muslim world. Islam's more than 1 billion followers live in 56 countries around the world, yet many in the West know little about it and are familiar only with the actions of a minority of radical extremists. This lecture outlines the second-largest and fastest-growing of the world's religions, which is part of the religious landscape of America and Europe, and has had a significant impact on world affairs.