World Wrestling Entertainment Hall of Famer Mark "The Undertaker" Calaway is a thirty-year veteran of the sports entertainment industry, and widely considered one of the best professional wrestlers of all time. Now retired from the ring, hi...

Justin Wren is a professional mixed martial artist, humanitarian aid-worker, and founder of Fight for the Forgotten: a non-profit benefiting the Mbuti Pygmy people of the Congo.

Mark Smith is an airline pilot, mixed martial arts referee, judge, and trainer, and corporate health and wellness advocate. Prior to his career in the private sector, Smith served his country as an Air Force F-16 fighter pilot, with tours a...

Jamar Neighbors is an actor and stand-up comedian.

Ira Glasser is a former director of the American Civil Liberties Union and a lifelong defender of every citizen's right to free speech. He is the subject of the 2020 documentary "Mighty Ira", available now on streaming video.

Scientist Lex Fridman researches human-centered artificial intelligence and autonomous vehicles at MIT, and is also the host of the Lex Fridman podcast.

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Andrew Yang is an American entrepreneur, the founder of Venture for America, and a 2020 Democratic presidential candidate.

Dr. Phil McGraw is an author, psychologist, and the host of the television show "Dr. Phil."

Johann Hari is a writer and journalist. His new book “Lost Connections” is available now.

Bill Ottman is an Internet entrepreneur and freedom of information activist based, and is also the CEO and co-founder of Minds. http://www.minds.com

Dr. Lindsey Fitzharris is an author and medical historian. She is the creator of the popular blog, The Chirurgeon's Apprentice and the host of the YouTube video series Under the Knife. Her book "The Butchering Art: Joseph Lister's Quest to...

Renée DiResta is the Director of Research at New Knowledge and a Mozilla Fellow in Media, Misinformation, and Trust.

Gary Taubes is a journalist, writer and low-carbohydrate diet advocate. Stephan Guyenet, PhD, is a neuroscientist and is also the founder and director of Red Pen Reviews.