Read a 2005 survey of 17,000 Muslims in 17 countries by the Pew Global Attitudes Project. Among its findings is that many Muslims see extremism as a threat to their countries.

Bassam Tibi is a professor of international relations at the University of Göttingen in Göttingen, Germany, and an expert on radical fundamentalism in political Islam throughout Europe and the Middle East.

Hassan Abbas is a research fellow at Harvard University’s Belfer Center for Science and International Affairs in Cambridge, Mass. He is an expert on religious extremism in South and Central Asia and is the author of a book on extremism in Pakistan.

Gideon Rose is managing editor of Foreign Affairs magazine and an expert on terrorism, among other issues, in the Middle East and South Asia. He is based in New York City.

Michael Radu is co-chairman of the Center on Terrorism, Counter-Terrorism and Homeland Security at the Foreign Policy Research Institute in Philadelphia. He has studied terrorist groups around the world and is an expert on terrorism and extremism in Turkey.

Sandra Mackey is a freelance journalist who has written widely on Islamic extremism, especially in Iraq and Lebanon. She is the author several books on Islam and politics in the Middle East including Mirror of the Arab World: Lebanon in Conflict (2008). She lives in Atlanta, Ga.

Bruce Hoffman is a professor in the security studies program at Georgetown University in Washington, D.C. He teaches graduate courses in terrorism and counterterrorism and insurgency and counterinsurgency, as well as other international security subjects.

Tawfik Hamid describes himself as a former member of an Islamic extremist movement Jamma’a Islameia who now speaks out for political and religious reform in the Muslim world.

Sohail Hashmi is an associate professor of international relations at Mount Holyoke College in South Hadley, Mass. He is an expert on Islam, pluralism, Islamic political thought and jihad. He posits that Islam lacks a tradition of political thought.