Supporters of a Pakistani traders group chanted slogans during an April 2008 rally to condemn the printing of Muhammad cartoons in Danish newspapers in Karachi, Pakistan. A Yale University book committee has refused to allow reprints of those cartoons in a book chronicling the controversy. Fareed Khan/AP hide caption

itoggle caption Fareed Khan/AP

Christopher Hitchens and Douglas Wilson debate whether religion is good for the world in Collision. www.collisionmovie.com hide caption

itoggle caption www.collisionmovie.com

Dalia Mogahed, one of 25 people tapped by President Obama to serve on an advisory council on faith-based issues. Mogahed may have met Obama only once, but to Muslims, she's a celebrity — thanks to the headscarf, or hijab, she wears every day. Coburn Dukehart/NPR hide caption

itoggle caption Coburn Dukehart/NPR