Suzanne O'Sullivan is a neurologist who sees many patients with psychosomatic disorders. Their symptoms may be psychological in origin, but their pain is real and physical — and the way we practice medicine, she argues, is making those and other health problems worse.

• SOURCES:
  • Suzanne O'Sullivan, neurologist and author of The Age of Diagnosis How Our Obsession with Medical Labels Is Making Us Sicker.

• RESOURCES:
  • The Age of Diagnosis: How Our Obsession with Medical Labels Is Making Us Sicker, by Suzanne O'Sullivan (2025).
  • "Associations of Depression, Anxiety, Worry, Perceived Stress, and Loneliness Prior to Infection With Risk of Post-COVID-19 Conditions," by Siwen Wang, Luwei Quan, Jorge Chavarro, Natalie Slopen, Laura Kubzansky, Karestan Koenen, Jae Hee Kang, Marc G. Weisskopf, Westyn Branch-Elliman, and Andrea Roberts (JAMA Psychiatry, 2022).
  • "How beliefs about coronavirus disease (COVID) influence COVID-like symptoms? – A longitudinal study." by Liron Rozenkrantz, Tobias Kube, Michael H Bernstein, and John D.E. Gabrieli (Health Psychology, 2022).
  • "Risk factors for worsening of somatic symptom burden in a prospective cohort during the COVID-19 pandemic," by Petra Engelmann, Bernd Löwe, Thomas Theo Brehm, Angelika Weigel, Felix Ullrich, Marylyn Addo, Julian Schulze Zur Wiesch, Ansgar Lohse, and Anne Toussaint (Frontier Psychology, 2022).
  • The Sleeping Beauties: And Other Stories of Mystery Illness, by Suzanne O'Sullivan (2021).
  • Brainstorm: Detective Stories from the World of Neurology, by Suzanne O'Sullivan (2018).
  • "The Trauma of Facing Deportation," by Rachel Aviv (The New Yorker, 2017).
  • It's All in Your Head: True Stories of Imaginary Illness, by Suzanne O'Sullivan (2015).
  • The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma, by Bessel van der Kolk (2014).
  • "Explaining the Rise in Youth Suicide," by David Cutler, Edward Glaeser,
    and Karen Norberg (National Bureau of Economic Research, 2001).

• EXTRAS:
  • Counted Out, documentary (2024).
  • "Bringing Data to Life," by People I (Mostly) Admire (2023).
  • "Adding Ten Healthy Years to Your Life," by People I (Mostly) Admire (2023).
  • "America’s Math Curriculum Doesn’t Add Up," by Freakonomics Radio (2019).
  • Race to Nowhere, documentary (2010).
  • Data Science for Everyone.

Reginald Dwayne Betts spent more than eight years in prison. Today he's a Yale Law graduate, a MacArthur Fellow, and a poet. His nonprofit works to build libraries in prisons so that more incarcerated people can find hope.

• SOURCES:
  • Reginald Dwayne Betts, founder and director of Freedom Reads, award-winning poet, and lawyer.

• RESOURCES:
  • Doggerel: Poems, by Reginald Dwayne Betts (2025).
  • “The Poet Writing on Prison Underwear,” by Adam Iscoe (The New Yorker, 2023).
  • The Voltage Effect, by John List (2022).
  • “If We Truly Believe in Redemption and Second Chances, Parole Should Be Celebrated,” by Reginald Dwayne Betts (The Washington Post, 2021).
  • Insurrections, by Rion Scott (2016).
  • The Secret History of Wonder Woman, by Jill Lepore (2014).
  • Zen and the Art of Motorcycle Maintenance: An Inquiry into Values, by Robert M. Pirsig (1974).
  • The Black Poets, by Dudley Randall (1971).
  • “For Freckle-Faced Gerald,” by Etheridge Knight (Poems from Prison, 1968).
  • Felon: An America Washi Tale, by Reginald Dwayne Betts.
  • Freedom Reads.

• EXTRAS:
  • “Can a Moonshot Approach to Mental Health Work?” by People I (Mostly) Admire (2023).
  • “Can Data Keep People Out of Prison?” by People I (Mostly) Admire (2023).
  • “The Price of Doing Business with John List,” by People I (Mostly) Admire (2022).
  • “Why Do Most Ideas Fail to Scale?” by Freakonomics Radio (2022).

Chemist Jack Szostak wants to understand how the first life forms came into being on Earth. He and Steve discuss the danger of "mirror bacteria," the origin of biology in poisonous chemicals, and the possibility that life might exist on other planets too. 

• SOURCES:
  • Jack Szostak, Nobel laureate and professor of chemistry at The University of Chicago.

• RESOURCES:
  • Is Earth Exceptional?: The Quest for Cosmic Life, by Mario Livio and Jack Szostak (2024)
  • "Q&A: How ‘Mirror Bacteria’ Could Take a Devastating Toll on Humanity," by Isabella Backman (Yale School of Medicine, 2024).
  • "The virtual circular genome model for primordial RNA replication," by Jack Szostak, Lijun Zhou, and Dian Ding (RNA, 2021).
  • "Protocells and RNA Self-Replication," by Gerald Joyce and Jack Szostak (Cold Spring Harbor Perspectives in Biology, 2018).
  • "The Narrow Road to the Deep Past: In Search of the Chemistry of the Origin of Life," by Jack Szostak (Angewandte Chemie International Edition, 2017).
  • "Jack Szostak on 'Life in the Lab' (And Autocatalytic Sets)" by Suzan Mazur (Huffington Post, 2014).
  • "Jack W. Szostak Interview" (The Nobel Prize, 2009).
  • "The Miller-Urey Experiment" (National Center for Science Education).
  • "From Old Vials, New Hints on Origin of Life," by Kenny Chang (New York Times, 2008).

• EXTRAS:
  • What Is It Like to Be an Addict?: Understanding Substance Abuse, by Owen Flanagan (2025)
  • "UPDATE: What It’s Like to Be Steve Levitt’s Daughters," by People I (Mostly) Admire (2024).
  • "We Can Play God Now," by Freakonomics Radio (2022).

Owen Flanagan's newest book details his 20-year dependence on alcohol and pills — and outlines his research on what addiction can tell us about the nature of consciousness.

• SOURCES:
  • Owen Flanagan, philosopher, neurobiologist, and professor emeritus at Duke University.

• RESOURCES:
  • What Is It Like to Be an Addict?: Understanding Substance Abuse, by Owen Flanagan (2025).
  • Consciousness Reconsidered, by Owen Flanagan (1993).
  • Against Happiness, by Owen Flanagan, Joseph E. LeDoux, Bobby Bingle, Daniel M. Haybron, Batja Mesquita, Michele Moody-Adams, Songyao Ren, Anna Sun, and Yolonda Y. Wilson. (2023).
  • The Bodhisattva's Brain: Buddhism Naturalized, by Owen Flanagan (2013).
  • The Really Hard Problem: Meaning in a Material World, by Owen Flanagan (2009).
  • Big Book, by Alcoholics Anonymous.
  • "Impact of the DSM-IV to DSM-5 Changes on the National Survey on Drug Use and Health," by Cristie Glasheen, Kathryn Batts, Rhonda Karg, Jonaki Bose, Sarra Hedden, and Kathryn Piscopo (Substance Abuse and Mental Health Services Administration, 2016).

• EXTRAS:
  • "Professor Carl Hart Argues All Drugs Should Be Legal — Can He Convince Steve?" by People I (Mostly) Admire (2021).
  • Drug Use for Grown-Ups: Chasing Liberty in the Land of Fear, by Carl Hart (2021).

The primatologist discusses the thrill of observing chimpanzees in the wild, the value of challenging orthodoxy, and why dying is her next great adventure.

• SOURCES:
  • Dr. Jane Goodall, GBE, founder of the Jane Goodall Institute and U.N. Messenger of Peace.

• RESOURCES:
  • The Book of Hope: A Survival Guide for Trying Times, by Jane Goodall, Douglas Abrams, and Gail Hudson (2021).
  • Jane, by Brett Morgen (2017).
  • “Remembering My Mentor: Robert Hinde,” by Jane Goodall (2017).
  • The Soul of an Octopus: A Surprising Exploration into the Wonder of Consciousness, by Sy Montgomery (2015).
  • Dr. Spock On Parenting: Sensible, Reassuring Advice for Today’s Parent, by by Benjamin Spock, M.D. (2001).
  • The Mentality of Apes, by Wolfgang Kohler (1976).
  • “Miss Goodall and the Wild Chimpanzees,” (1965).

• EXTRAS:
  • Roots and Shoots.
  • Jane Goodall Hopecast.
  • The Jane Goodall Institute.
  • Grameen Foundation.
  • “A Cross Between Sherlock Holmes and Indiana Jones,” by People I (Mostly) Admire (2022).
  • “‘No One Can Resist a Jolly, Happy Pig,'” by People I (Mostly) Admire (2022).

Hank Green is an internet phenomenon and a master communicator, with a plan to reform higher education. He and Steve talk about the video blog that launched Hank’s career, the economics of the internet, and how a cancer diagnosis prompted him to become a stand-up comedian.

• SOURCES:
  • Hank Green, founder of Complexly and science communicator

• RESOURCES:
  • Complexly
  • CrashCourse YouTube Channel
  • SciShow YouTube Channel
  • Vlogbrothers YouTube Channel
  • The Show with Ze Frank
  • Study Hall
  • "An Absolutely Remarkable Thing," by Hank Green (2018)
  • "A Beautifully Foolish Endeavor," by Hank Green (2020)
  • "So, I've got cancer," by Vlogbrothers (2023)
  • "My Cancer Press Tier List," by Vlogbrothers (2023)
  • "Between Two Kingdoms: A Memoir of a Life Interrupted" by Suleika Jaouad (2021)
  • "The Impact of Legalized Abortion on Crime," by John Donohue III and Steve Levitt (The Quarterly Journal of Economics, 2001)
  • "Hoodwinked?" by Stephen Dubner and Steve Levitt (New York Times, 2006)
  • "An Ancient Roman Shipwreck May Explain the Universe," by SciShow (2024)

• EXTRAS:
  • "John Green’s Reluctant Rocket Ship Ride," by People I (Mostly) Admire (2022)
  • "Suleika Jaouad’s Survival Mechanisms," by People I (Mostly) Admire (2024)

Jonathan Levin is an academic economist who now runs one of the most influential universities in the world. He tells Steve how he saved Comcast a billion dollars, why he turned down Steve’s unusual pitch to come to the University of Chicago, and why being a nice guy makes him a better college president.

• SOURCE:
  • Jonathan Levin, president of Stanford University.  

• RESOURCES:
  • "Income Segregation and Intergenerational Mobility Across Colleges in the United States," by Raj Chetty, John N Friedman, Emmanuel Saez, Nicholas Turner, and Danny Yagan (The Quarterly Journal of Economics, 2020).
  • "Jonathan Levin: The Most Recent John Bates Clark Medal Winner," by Steve Levitt (Freakonomics Blog, 2011).
  • "Winning Play in Spectrum Auctions," by Jeremy Bulow, Jonathan Levin, and Paul Milgrom (NBER Working Paper, 2009).
  • "Information and Competition in U.S. Forest Service Timber Auctions," by Susan Athey and Jonathan Levin (Journal of Political Economy, 2001).

• EXTRAS:
  • Vintage Pokémon card pack Instagram video, by Tyler Thrasher (2025).
  • "Higher Education Is Broken. Can It Be Fixed?" by People I (Mostly) Admire (2023).
  • "How Much Are the Right Friends Worth?" by People I (Mostly) Admire (2022).

Sarah Hart investigates the mathematical structures underlying musical compositions and literature. Using examples from Monteverdi to Lewis Carroll, Sarah explains to Steve how math affects how we hear music and understand stories.   

• SOURCE:
  • Sarah Hart, professor emerita of mathematics at the University of London.

• RESOURCES:
  • Once Upon a Prime: The Wondrous Connections Between Mathematics and Literature, by Sarah Hart (2023).
  • "Ahab's Arithmetic: The Mathematics of Moby-Dick," by Sarah B. Hart (Journal of Humanistic Mathematics, 2021).
  • "Online Lecture: The Mathematics of Musical Composition," by Sarah Hart (Gresham College, 2020).
  • Black Mirror: Bandersnatch, film (2018).
  • The Luminaries: A Novel, by Eleanor Catton (2013).
  • Not Quite What I Was Planning: Six-Word Memoirs by Writers Famous and Obscure, edited by Rachel Fershleiser and Larry Smith (2008).
  • Les Revenentes, by Georges Perec (1972).
  • A Void, by Georges Perec (1969).
  • Cent Mille Milliards de Poèmes, by Raymond Queneau (1961).
  • Through the Looking-Glass, and What Alice Found There, by Lewis Carroll (1871).
  • Alice's Adventures in Wonderland, by Lewis Carroll (1865).
  • OuLiPo.

• EXTRAS:
  • "The Joy of Math With Sarah Hart," by People I (Mostly) Admire (2023).
  • "Mathematician Sarah Hart on Why Numbers are Music to Our Ears," by People I (Mostly) Admire (2021).

Sarah Stein Greenberg runs Stanford’s d.school, which teaches design as a mode of problem solving. She and Steve talk about what makes her field different from other academic disciplines, how to approach hard problems, and why brainstorms are so annoying.

• SOURCE:
  • Sarah Stein Greenberg, executive director of the Hasso Plattner Institute of Design at Stanford University.

• RESOURCES:
  • Creative Acts for Curious People: How to Think, Create, and Lead in Unconventional Ways, by Sarah Stein Greenberg (2021).
  • Noora Health.
  • Civilla.
  • Substantial.
  • Rare.
  • Sarah Stein Greenberg wildlife photography.

• EXTRAS:
  • "Feeling Sound and Hearing Color," by People I (Mostly) Admire (2024).
  • "Why Are Boys and Men in Trouble?" by People I (Mostly) Admire (2024).
  • "What’s Impacting American Workers?" by People I (Mostly) Admire (2024).
  • "Richard Dawkins on God, Genes, and Murderous Baby Cuckoos," by People I (Mostly) Admire (2024).
  • "The World’s Most Controversial Ornithologist," by People I (Mostly) Admire (2024).
  • "How PETA Made Radical Ideas Mainstream," by People I (Mostly) Admire (2024).
  • "Pay Attention! (Your Body Will Thank You)," by People I (Mostly) Admire (2024).
  • "How to Have Great Conversations," by People I (Mostly) Admire (2024).
  • "Suleika Jaouad’s Survival Mechanisms," by People I (Mostly) Admire (2024).
  • "Daron Acemoglu on Economics, Politics, and Power," by People I (Mostly) Admire (2024).
  • "Nobel Laureate Claudia Goldin on 'Greedy Work' and the Wage Gap," by People I (Mostly) Admire (2023).
  • "A Rockstar Chemist and Her Cancer-Attacking 'Lawn Mower,'" by People I (Mostly) Admire (2022).
  • "Daniel Kahneman on Why Our Judgment is Flawed — and What to Do About It," by People I (Mostly) Admire (2021).
  • "Why Is Richard Thaler Such a ****ing Optimist?" by People I (Mostly) Admire (2021).

In her book, Rumbles, medical historian Elsa Richardson explores the history of the human gut. She talks with Steve about dubious medical practices, gruesome tales of survival, and the things that medieval doctors may have gotten right.

• SOURCE:
  • Elsa Richardson, medical historian at the University of Strathclyde.

• RESOURCES:
  • Rumbles: A Curious History of the Gut: The Secret Story of the Body's Most Fascinating Organ, by Elsa Richardson (2024).
  • Michael Levitt retirement speech (2024).
  • "Was There Really a Hawthorne Effect at the Hawthorne Plant? An Analysis of the Original Illumination Experiments," by Steven D. Levitt and John A. List (NBER Working Paper, 2009).
  • "Floating Stools — Flatus versus Fat," by Michael D. Levitt and William C. Duane (The New England Journal of Medicine, 1972).
  • "Factors Influencing Pulmonary Methane Excretion in Man," by John H. Bond, Rolf R. Engel, and Michael D. Levitt (Journal of Experimental Medicine, 1971).
  • The Expression of the Emotions in Man and Animals, by Charles Darwin (1872).
  • The Levitt Lab Founding School Leader, job listing.
  • The Levitt Lab, information page.

• EXTRAS:
  • "An Update on the Khan World School," by People I (Mostly) Admire (2023).
  • “Is This the Future of High School?” by People I (Mostly) Admire (2022).
  • “Sal Khan: ‘If It Works for 15 Cousins, It Could Work for a Billion People,'” by People I (Mostly) Admire (2021).
  • "The Power of Poop," by Freakonomics Radio (2011).