Neil Degrasse Tyson, Richard Dawkins, Adam Gopnik, Matt Welch, and Angela Rye.

Esquire TV's "The Runner-Up" star Clay Aiken, "The Story" author Judith Miller, "Thomas Jefforson" author Jon Meacham, CNBC chief international correspondent Michele Caruso Cabrera, Center for American Progress president Neera Tanden.

The Interview: Sister Helen Prejean. The Panel: Jennifer Granholm, Doug Heye, Lawrence Wilkerson. Mid-Show Guest: Talib Kweli.

"Pretty Ladylike" author Senator Claire McCaskill (D-MO), WTF's Marc Maron, Rep. Donna Edwards (D-MD), "Conservatarian Manifesto" author Charles Cooke, "The Blue Zones Solution" author Dan Buettner.

GOP Presidential candidate & Ex-Senator Rick Santorum (R-PA), Representative Dana Rohrabacher (R-CA), Ex-State Senator Wendy Davis (D-TX), Washington Post national reporter Robert Costa and Senior Editor for The Daily Beast Michael Weiss.

Jane Goodall, John Cleese, S.E. Cupp, and Ron Reagan.

EPA Administrator Gina McCarthy, Georgetown professor Michael Eric Dyson, "The Selfie Vote" author Kristen Soltis Anderson, "End of Discussion" co-writer Mary Katherine Ham, and "Trainwreck" director & "Sick in the Head" author Judd Apatow.

Bernie Sanders, Katrina Vanden Heuvel, Lawrence Lessig, Johann Hari, and John Feehery.

"A Fighting Chance" author Senator Elizabeth Warren (D-MA), "Live Right and Find Happiness" author Dave Barry, "In Defense of Liberal Education" author Fareed Zakaria, "Bad Religion" author Ross Douthat and Roll Call editor-in-chief Christina Bellantoni.

Bill's guests include comedy legend Billy Crystal, MSNBC "Now" host Alex Wagner, Ex-Rhode Island Governor Lincoln Chafee, consumer advocate Erin Brockovich, and ESPN commentator Will Cain.

Chris Matthews, Governor George Pataki, Mark Cuban and Jorge Ramos.

Bill's guests include "Inside Out" actor Lewis Black, ex-representative Rick Lazio (R-NY), ex-senior CIA and FBI official Philip Mudd, ex-Ohio state senator Nina Turner (D-OH), and "Superpower" author Ian Bremmer.

Author Salman Rushdie, cable legend Keith Olbermann, Daily Beast columnist Michael Moynihan, political columnist Linda Chavez and actor Wendell Pierce.

Bill's guests include Angus King, Chrystia Freeland, Gavin Newsom, Andy Cohen, and Ben Domenech.

Bill's guests include Democratic President hopeful, Senator Bernie Sanders (I-VT), Representative Luis Gutiérrez (D-IL), "¡Adios America!" author Ann Coulter, MSNBC contributor Joy Reid and Daily Caller's senior contributor Matt Lewis.

The Interview: Michael Mann. The Panel: Mary Matalin, Steve Schmidt, Lt. Governor Gavin Newsom (D-CA). Mid-Show Guest: Caitlin Flanagan.

Ernest Moniz, Rob Thomas, Andrew Sullivan, Anne-Marie Slaughter and Patrick J. Kennedy.

Bill's guests include Jay Leno, Michael Steele, Dylan Ratigan, Asra Nomani, and Paul Reiser.

Ex-Governor Howard Dean (D-VT), comedian and "Black and White" actor Bill Burr, "America in Retreat" author Bret Stephens, Washington Post's Nia-Malika Henderson, and The Atlantic's James Fallows.

This weeks guests include comedy legend Mel Brooks, Representative Joaquin Castro (D-TX), "Citizenfour" director Laura Poitras, BBC World News anchor Kitty Kay, and "The Entrepreneurial Instinct" author Monica Mehta.

Celebrity chef & "Fresh Off the Boat" author Eddie Huang, activist Robert F. Kennedy, Jr., Daily Beast contributor Ana Marie Cox, Weekly Standard senior editor Christopher Caldwell, and G.O.P. consultant Liz Mair.

Bill's guests include film-maker & "Carsick" author John Waters, "Heretic" author Ayaan Hirsi Ali, Democratic president Heather McGhee, and "By the People" author Charles Murray.

Bill's guests include "Jeff Ross Roasts Criminals" comic Jeff Ross, actor and environmentalist Ed Begley Jr., Daily Beast columnist Ron Christie, The Other 98% director Alexis Goldstein, and Slate's "The Gist" host Mike Pesca.

David Spade, Maxine Waters, Grover Norquist, Tulsi Gabbard, and Roger Stone.

Comedy legend Jay Leno, literary icon Salman Rushdie, Ex-HP CEO Carly Fiorina, Chris Hardwick and Paul Begala.