TONIGHT: Stephen Colbert welcomes the host of Countdown with Keith Olbermann, Keith Olbermann!

TONIGHT: Stephen Colbert welcomes the host of The Al Franken Show, Al Franken!

TONIGHT: Stephen Colbert welcomes ABC News' John Stossel!

TONIGHT: Stephen Colbert welcomes Professor of Biology at Brown University, Ken Miller!

TONIGHT: Stephen Colbert welcomes the host of "This Week", George Stephanopoulos!

TONIGHT: Stephen Colbert welcomes author and blogger, Andrew Sullivan!

TONIGHT: Stephen Colbert welcomes the author of "Teacher Man: A Memoir", Frank McCourt!

TONIGHT: Stephen Colbert welcomes National Public Radio's legal affairs correspondent, Nina Totenberg!

TONIGHT: Stephen Colbert welcomes former FEMA director, Michael Brown!

TONIGHT: Stephen Colbert welcomes "Washington Post" fashion editor, Robin Givhan!

TONIGHT: Stephen Colbert welcomes the author of "Self-Made Man: One Woman's Journey into Manhood and Back" Norah Vincent!

TONIGHT: Stephen Colbert welcomes CNN commentator and the co-author of "Take It Back: Our Party, Our Country, Our Future", Paul Begala!

TONIGHT: Stephen Colbert welcomes Rev. Jesse Jackson!

TONIGHT: Stephen Colbert welcomes the author of "Manliness", Harvey Mansfield!

TONIGHT: Stephen Colbert welcomes the author of "What the Dog Did: Tales from a Formerly Reluctant Dog Owner", Emily Yoffe!

TONIGHT: Stephen Colbert welcomes the author of "It's My Party, Too: The Battle for the Heart of the GOP and the Future of America", Christine Todd Whitman!

TONIGHT: Stephen Colbert welcomes California Senator Barbara Boxer!

TONIGHT: Stephen Colbert welcomes former CIA Director James Woolsey!

TONIGHT: Stephen Colbert welcomes the author of "The Case for Peace: How the Arab-Israeli Conflict Can be Resolved", Alan Dershowitz!

TONIGHT: Stephen Colbert welcomes the author of "The Assassins' Gate: America in Iraq", George Packer!

TONIGHT: Stephen Colbert welcomes the author of Natural Radiance: Awakening to Your Great Perfection, Lama Surya Das!

TONIGHT: Stephen Colbert welcomes the author of Come Hell or High Water: Hurricane Katrina And the Color of Disaster, Michael Eric Dyson!

TONIGHT: Stephen Colbert welcomes the editor of The Weekly Standard, Bill Kristol!

TONIGHT: Stephen Colbert welcomes the author of Adventures in Missing the Point: How the Culture-Controlled Church Neutered the Gospel, Tony Campolo!

TONIGHT: Stephen Colbert welcomes the director of debate at King's College, Brett O'Donnell!

TONIGHT: Stephen Colbert welcomes author and internet blogger, Arianna Huffington!

TONIGHT: Stephen Colbert welcomes the author of The End of Poverty: Economic Possibilities for Our Time, Jeffrey Sachs!

TONIGHT: Stephen Colbert welcomes the author of The Shere Hite Reader, Shere Hite!

TONIGHT: Stephen Colbert welcomes the author of The Broken Branch: How Congress Is Failing America and How to Get It Back on Track, Norman Ornstein!

TONIGHT: Stephen Colbert welcomes the author of Born Fighting: How the Scots-Irish Shaped America, James Webb!

TONIGHT: Stephen Colbert welcomes actress, Lorraine Bracco!

TONIGHT: Stephen Colbert welcomes the author of Thank You for Smoking : A Novel, Christopher Buckley!

TONIGHT: Stephen Colbert welcomes the host of Countdown with Keith Olbermann, Keith Olbermann!

TONIGHT: Stephen Colbert welcomes the host of The Al Franken Show, Al Franken!

TONIGHT: Stephen Colbert welcomes the author of A Guy's Guide to Being a Man's Man, Frank Vincent!

Tonight Stephen welcomes Dateline NBC anchor Stone Philips.

TONIGHT: Stephen Colbert welcomes 60 Minutes correspondent, Steve Kroft!

TONIGHT: Stephen Colbert welcomes Advisor to the U.S. Presidential Envoy in Iraq, Dan Senor!

Tonight Stephen welcomes Steven Johnson, author of Everything Bad Is Good For You.

Tonight Stephen welcomes environmental politician, Robert F. Kennedy Jr.

Tonight Stephen welcomes mammologist and paleontologist Tim Flannery, author of The Weather Makers.

TONIGHT: Stephen Colbert welcomes the author of Impostor: How George W. Bush Bankrupted America and Betrayed the Reagan Legacy, Bruce Bartlett!

TONIGHT: Stephen Colbert welcomes the producer of Wal-Mart: The High Cost of Low Price, Outfoxed: Rupert Murdoch's War on Journalism, and most recently, The Big Buy: How Tom Delay Stole Congress, Robert Greenwald!

Tonight Stephen welcomes ocweekly.com's Ask a Mexican columnist Gustavo Arellano.

Tonight Stephen welcomes Bart Ehrman, author of Misquoting Jesus.

Tonight Stephen welcomes Angela "Bay" Buchanan, President of The American Cause.

Tonight Stephen welcomes the author of The Great Deluge, Douglas Brinkley.

TONIGHT: Stephen Colbert welcomes the author of No god But God, Reza Aslan!

Tonight Stephen welcomes the host of Hardball, Chris Matthews.

TONIGHT: Stephen Colbert welcomes the author of To Hell With All That: Loving and Loathing Our Inner Housewife, Caitlin Flanagan!

Tonight Stephen welcomes journalist Christpher Noxon, author of Rejuvenile.

TONIGHT: Stephen Colbert welcomes the author of Painting the Map Red: The Fight to Create a Permanent Republican Majority, Hugh Hewitt!

Tonight Stephen welcomes skateboarding legend Tony Hawk.

Tonight Stephen welcomes editor in chief for U.S. News World Report, Mort Zuckerman.

TONIGHT: Stephen Colbert welcomes the editor of The Weekly Standard, Bill Kristol!

TONIGHT: Stephen Colbert welcomes the author of American Gospel: God, the Founding Fathers, and the Making of a Nation, Jon Meacham!

TONIGHT: Stephen Colbert welcomes the author of Quit Digging Your Grave with a Knife and Fork: A 12-Stop Program to End Bad Habits and Begin a Healthy Lifestyle and the Governor of Arkansas, Gov. Mike Huckabee!

TONIGHT: Stephen Colbert welcomes the author of Chasing Ghosts: A Soldier's Fight for America from Baghdad to Washington, Paul Rieckhoff!

TONIGHT: Stephen Colbert welcomes the author of Shanks For Nothing, Rick Reilly!

TONIGHT: Stephen Colbert welcomes editor of the New York Times, Frank Rich!

TONIGHT: Stephen Colbert welcomes editor of The Smoking Gun.com, Bill Bastone!

TONIGHT: Stephen Colbert welcomes the former Secretary of State, Madeleine Albright!

Tonght, Democratic hopeful for Senate in Connecticut, Ned Lamont.

Tonight former editor for the New Republic and author of The Good Fight: Why Liberals--And Only Liberals--Can Win the War On Terror and Make America Great Again, Peter Beinart.

Tonight former attorney and professor of philisophy Linda R. Hirshman, author of Get to Work: A Manifesto for Women in the World.

TONIGHT: Stephen Colbert welcomes the Assistant Curator and Chair, Vertebrate Zoology at the Center for Systematic Biology & Evolution, Ted Daeschler!

Tonight Stephen welcomes Dateline NBC anchor Stone Philips.

Tonight Stephen welcomes CNN's chief international correspondent Christiane Amanpour.

Tonight Stephen welcomes Cornell University scientist and author of Roving Mars Steven Squyres.

Tonight Stephen welcomes Ramesh Ponnuru, senior editor of the National Review and author of The Party of Death: The Democrats, the Media, the Courts and the Disregard for Human Life.

Tonight Stephen welcomes political commentator of PBS's NewsHour with Jim Lehrer and author of Eyewitness to Power: The Essence of Leadership Nixon to Clinton, David Gergen.

Tonight Stephen welcomes mammologist and paleontologist Tim Flannery, author of The Weather Makers.

Tonight Stephen welcomes legendary musician Neil Young.

Tonight Stephen welcomes Geoffrey Nunberg, professor of linguistics and columnist for the New York Times and author of Talking Right: How Conservatives Turned Liberalsim into a Tax Raising, Latte-Drinking, Sushi-Eating, Volvo-Driving, New York Times-Reading, Body Piercing, Hollywood Loving, Left-Wing Freak Show.

Tonight Stephen welcomes ocweekly.com's Ask a Mexican columnist Gustavo Arellano.

Tonight Stephen welcomes Bart Ehrman, author of Misquoting Jesus.

Tonight Stephen welcomes Angela "Bay" Buchanan, President of The American Cause.

Tonight Stephen welcomes comedian Martin Short.

Tonight Stephen welcomes Marc Bowden, author of Guests of the Ayatollah: The First Battle in America's War With Militant Islam.

Tonight Stephen welcomes the host of Hardball, Chris Matthews.

Tonight Stephen welcomes form CIA agents and author of Blow the House Down, Robert Baer.

Tonight Stephen welcomes actor, performer, rapper, playwright and educator Will Power.

Tonight Stephen welcomes Amy Sedaris, star of Strangers with Candy.

Tonight Stephen welcomes skateboarding legend Tony Hawk.

Tonight former defense analyst Daniel Ellsberg.

Tonight Stephen welcomes back Arianna Huffington, blogger and author of On Becoming Fearless...in Love, Work, and Life

Tonight Stephen welcomes actor Ted Danson.

Tonight Stephen welcomes Pulitzer Prize winning investigative journalist and the Reva and David Logan Distinguished Professor at UC Berkeley's Graduate School of Journalism, Lowell Bergman.

Tonight Stephen welcomes the host of Scarborough Country, Joe Scarborough.

Tonight Stephen welcomes former NBC Nightly News anchor Tom Brokaw.

Tonight Stephen welcomes journalist and author of The One That Got Away: A Memoir, Howell Raines

Tonight Stephen Welcomes the president of the Catholic League, William Donohue.

Tonight Stephen welcomes Democracy Now! host and co-author of Static: Government Liars, Media Cheerleaders, and the People Who Fight Back, Amy Goodman.

Tonight Stephen welcomes musician Randy Newman.

Tonght, Democratic hopeful for Senate in Connecticut, Ned Lamont.

Tonight former editor for the New Republic and author of The Good Fight: Why Liberals--And Only Liberals--Can Win the War On Terror and Make America Great Again, Peter Beinart.

Tonight former attorney and professor of philisophy Linda R. Hirshman, author of Get to Work: A Manifesto for Women in the World.

Tonight Stephen welcomes lawyer and co-founder of the Innocence Project, Barry Scheck.

Tonight, New York Times columnist and author of Forty Million Dollar Slaves: The Rise, Fall and Redemption of the Black Athlete, Bill Rhoden.

Tonight cultural anthropologist Alexandra Robbins, author of The Overachievers: The Secret Life of Driven Kids.

Tonight campaign director for MoveOn.org, Eli Pariser.

Tonight Stephen welcomes Ramesh Ponnuru, senior editor of the National Review and author of The Party of Death: The Democrats, the Media, the Courts and the Disregard for Human Life.

Tonight Stephen welcomes political commentator of PBS's NewsHour with Jim Lehrer and author of Eyewitness to Power: The Essence of Leadership Nixon to Clinton, David Gergen.

Tonight Stephen welcomes documentary filmmaker and host of 30 Days, Morgan Spurlock.

Tonight Stephen welcomes legendary musician Neil Young.

Tonight Stephen welcomes Geoffrey Nunberg, professor of linguistics and columnist for the New York Times and author of Talking Right: How Conservatives Turned Liberalsim into a Tax Raising, Latte-Drinking, Sushi-Eating, Volvo-Driving, New York Times-Reading, Body Piercing, Hollywood Loving, Left-Wing Freak Show.

Tonight Stephen welcomes economist and colmnist Paul Krugman, author of The Great Unraveling: Losing Our Way in the New Century.

Tonight Stephen welcomes writer and correspondent for MTV News, Gideon Yago

Tonight Stephen welcomes mathematician Janna Levin, author of A Madman Dreams of Turing Machines.

Tonight Stephen welcomes comedian Martin Short.

Tonight Stephen welcome country music star Toby Keith.

Tonight Stephen welcomes record setting Jeopardy champion and author of Brainiac: Adventures in the Curious, Competetive, Compulsive World of Trivia Buffs, Ken Jennings

Tonight Stephen welcomes ESPN's Sports Guy columnist and author of Now I Can Die In Peace: How ESPN's Sports Guy Found Salvation with a Little Help from Nomar, Pedro, Shawshank, and the 2004 Red Sox, Bill Simmons

Tonight Stephen welcomes actor, performer, rapper, playwright and educator Will Power.

Tonight Stephen welcomes New York Times columnist Frank Rich, author of The Greatest Story Ever Sold: The Decline and Fall of Truth from 9/11 to Katrina.

Tonight Stephen welcomes Democratic political consultant James Carville.

Tonight former defense analyst Daniel Ellsberg.

Tonight Stephen welcomes back Arianna Huffington, blogger and author of On Becoming Fearless...in Love, Work, and Life

Tonight Stephen welcomes actor Ted Danson.

Tonight Stephen welcomes Pulitzer Prize winning investigative journalist and the Reva and David Logan Distinguished Professor at UC Berkeley's Graduate School of Journalism, Lowell Bergman.

Tonight Stephen welcomes co-founder of Apple Computers, Steve Wozniak.

Tonight Stephen welcomes Michael Lewis, author of The Blind Side: Evolution of a Game.

Tonight Stephen welcomes union leader and author of A Country That Works: Getting America Back on Track, Andy Stern.

Tonight Stephen welcomes North Dakota Senator Byron Dorgan, author of Take This Job and Ship It: How Corporate Greed And Brain-Dead Politics Are Selling Out America.

Tonight Stephen welcomes Democracy Now! host and co-author of Static: Government Liars, Media Cheerleaders, and the People Who Fight Back, Amy Goodman.

Tonight Stephen welcomes musician Randy Newman.

Tonight Stephen welcomes journalist and author of Female Chauvinist Pigs: Women and the Rise of Raunch Culture, Ariel Levy.

Tonight Stephen reveals the winner of the Green Screen Challenge. Plus, another Tek Jansen Adventure.

Tonight Stephen welcomes Montana Governor Brian Schweitzer

Tonight Stephen welcomes lawyer and co-founder of the Innocence Project, Barry Scheck.

Tonight Stephen celebrates his 1st anniversary episode with Oxford Professor of Biology and author of The God Delusion Richard Dawkins.

Tonight Stephen welcomes former special assistant to President Bush and author of Tempting Faith: An Inside Story of Political Seduction, David Kuo.

Tonight Stephen welcomes Nobel Prize winning chemist Dr. Peter Agre. Plus Stephen talks to Jim Gilchrist, founder of The Minuteman Project.

Tonight Stephen welcomes musician Barry Manilow.

Tonight Stephen welcomes actor and politcal activist Tim Robbins.

Tonight Stephen welcomes magician Penn Jillette.

Tonight Stephen welcomes political activist Ronald Reagan Jr.

Tonight Stephen welcoms ABC News correspondent and co-author of The Way to Win: Taking the White House in 2008, Mark Halperin.

Combined with the Daily Show for the night, Stephen talks to Warren Beatty by phone, Rep. Robert Wexler via satellite and Rep. Eleanor Holmes Norton via satellite.

Tonight Stephen welcomes CNN anchor Jeff Greenfield.

Tonight Stephen welcomes the founder of FIRST and President of DEKA Research and Development Corporation, Dean Kamen.

Tonight Stephen welcomes former CBS News anchor Dan Rather.

Tonight Stephen welcomes CEO of Timberland, Jeff Swartz.

Tonight Stephen welcomes Al Franken and paleontologist Dr. Michael Novacek.

Tonight Stephen welcomes Richard Linklater, director of Fast Food Nation.

Tonight Stephen welcomes PBS News Hour anchor and author of The Phony Marine: A Novel, Jim Lehrer.

Tonight Stephen welcomes comedian Harry Shearer.

Tonight Stephen welcomes screenwriter and author of I Feel Bad About My Neck: And Other Thoughts on Being a Woman, Nora Ephron.

Tonight Stephen welcomes ESPN commentator and author of Miracle on 49th Street, Mike Lupica.

Tonight Stephen welcomes computer game designer Will Wright.

Tonight Stephen welcomes economist and co-author of Freakonomics: A Rogue Economist Explores the Hidden Side of Everything, Steven D. Levitt.

Tonight Stephen welcomes the president of New York University, John Sexton.

Tonight Stephen welcomes the fromer head of the Human Genome Project and author of The Language of God: A Scientist Presents Evidence for Belief, Francis Collins.

Tonight Stephen welcomes Princeton ethicist, animal rights activist and co-author of The Way We Eat: Why Our Food Choices Matter, Dr. Peter Singer

Tonight Stephen welcomes nationally syndicated columnist and author of The Commitment: Love, Sex, Marriage, and My Family, Dan Savage.

Tonight Stephen welcomes historian and author of Team of Rivals, The Political Genius of Abraham Lincoln, Doris Kearns Goodwin.

Tonight Stephen welcomes a writer for the Village Voice and Rolling Stone and author of Breaking Open the Head: A Psychedelic Journey into the Heart of Contemporary Shamanism, Daniel Pinchbeck.

Tonight Stephen welcomes the retired CEO of General Electric, Jack Welch.

Tonight Stephen welcomes the leader in the field of mind body medicine, Deepak Chopra.

Stephen Colbert vs the Decemberists.