Terry Gross

On HBO's The Wire, actor Michael K. Williams plays Omar Little, a stick-up guy who robs only drug dealers. Omar has a scar running down his face. That's not a prosthetic scar; it's real. Williams tells Terry Gross the story behind his scar — and lots of other stories about himself and Omar.

Clark Johnson has worked as a director on several of TV's most memorable cop shows, including The Shield, Homicide: Life on the Street and the pilot episode of the critically acclaimed HBO series The Wire. This season, he's appearing on camera as well, as The Wire's City Editor Gus Haynes.

The leading African-American actor of his generation and the first African-American to win the best-actor Oscar, Sidney Poitier may be best remembered for the classic In the Heat of The Night. That film took a best-picture Oscar; it's out now in a 40th-anniversary edition DVD.

He made his name as a martial-arts star, but these days, Chuck Norris is most often seen standing behind Republican presidential candidate Mike Huckabee. It's been said, in fact, that that Norris' position as an unofficial running mate offers the campaign a jolt of manliness.

Editor and cofounder of the conservative Washington-based political magazine, The Weekly Standard, and an opinion columnist for The New York Times, William Kristol is a neoconservative voice on the Iraq war; he was among those who advocated for the U.S. to remove Saddam Hussein from power before Sept. 11, 2001.

Carl Conetta co-directs the Project on Defense Alternatives, a defense-policy think tank. Earlier, he was a research fellow at the Institute for Defense and Disarmament Studies; he served for three years as editor of their journal, Defense and Disarmament Alternatives, and of the Arms Control Reporter.

Baghdad-born activist Yanar Mohammed directs the Organization of Women's Freedom in Iraq.

Col. Lawrence Wilkerson was chief of staff for former Secretary of State Colin Powell; he became an outspoken critic of the Bush administration after leaving the State Department in January 2005.

Lawrence Wright is an author, screenwriter, playwright and a staff writer for The New Yorker magazine. He sits on the Council on Foreign Relations, and he won a Pulitzer Prize for his book The Looming Tower: Al-Qaeda and the Road to 9/11.

Iraqi-born professor Kanan Makiya teaches Islamic and Middle Eastern studies at Brandeis University, outside Boston. He is one of the leading Arab intellectuals who called for the removal of Saddam Hussein; he also advised the Bush administration before the invasion of Iraq.