John Legend, Mayor Michael Nutter, Chris Matthews

Episodes

Andrew Sullivan, Richard Freeman

Chris Beam, Gary Rosen

Gov. Mike Huckabee, Matt Taibbi

Norman Ornstein, Muhammad Yunus

Neil Shubin

Peter Hopkins, Jared Cohen

Deborah Tannen

Lou Dobbs, David Levy

Allan Sloan, Eric Weiner

Malcolm Gladwell, Andrew Young

Stephen Colbert's Sport Report

Debra Dickerson, Charles Nesson

Marjane Satrapi, Rick Warren

Joe Quesada, Alex Ross

Carl Hiaasen, Frans de Waal

Tim Harford, Andrew Napolitano

Tony Campolo, Jacob Weisberg

Angelo Falcon, Bob Dole

Richard Brookhiser, Tad Devine

Mark Moffett

Aubrey de Grey, Philip Zimbardo

Gov. Eliot Spitzer, Eleanor Holmes Norton, Lisa Randall

David Gracer, Richard Thompson Ford

John Feinstein, Leonard Nimoy

Henry Louis Gates Jr.

Tony Snow

Richard Brookhiser, Ingrid Newkirk

Lorin Maazel, Shashi Tharoor

William Donohue, Howard Dean, Jennifer 8. Lee

Robert Reich, Gregory Rodriguez

John Legend

George McGovern

Geraldo Rivera

Howard Kurtz

Hussein Ibish, Sudhir Venkatesh

Samantha Power

Carole King

Dee Dee Myers

Dean Kamen

Eric Alterman, Michael Reynolds

Van Jones

R.E.M.

Clay Shirky

Trevor Paglen, Jesse Ventura

Madeline Albright

Jeff Gore

Robin Wright

John Legend, Mayor Michael Nutter, Chris Matthews

Michelle Obama, The Roots

Philadelphia Eagles Cheerleaders, Gov. Ed Rendell

Hillary Clinton, Patrick Murphy, John Edwards, Barack Obama

Fr. James Martin, Sen. Bernie Sanders

Susan Jacoby

Mitch Albom

Maria Shriver

Feist

Anne Lamott

Donna Brazile, Noah Feldman

James Kunstler

Carl Hiaasen

Nathan Gunn

Hasan Elahi, George Johnson

Arianna Huffington

Dr. Mehmet Oz

Jennifer Hooper McCarty

Laura Dern, Grover Norquist

Andrei Cherny

Tony Perkins, Brian Greene

Sen. Claire McCaskill

Tad Devine, David Sirota

Jon Paskowitz

George Will

Rep. Bob Barr, Salman Rushdie

Pat Buchanan

Phil Weiss

Alan Rabinowitz

David Hajdu

Winona LaDuke, Dixon Despommier