Elizabeth Howell is working to address maternal mortality in the United States.

Veterinarian, dog trainer and animal behaviorist Ian Dunbar understands our pets' point of view. By training dog owners in proper conduct (as much as he trains the dogs themselves), he hopes to encourage better relationships with dogs -- not to mention their friends and children, too.

A practicing surgeon for three decades, Sherwin Nuland witnessed life and death in every variety. Then he turned to writing, exploring what there is to people beyond just anatomy.

Stuart Brown's research shows play is not just joyful and energizing -- it's deeply involved with human development and intelligence. Through the National Institute for Play, he's working to better understand its significance.

Baba Shiv studies how “liking” and “wanting” shape the choices we make, and what that means in the world of marketing.

Drawing on a rich cultural and personal history, Olúfẹ́mi Táíwò studies philosophy of law, social and political philosophy, Marxism, and African and Africana philosophy.

A writer and stand-up comedian, Aparna Nancherla is one of the most exciting new voices to hit the comedy scene.

Bob Langert consults, writes and speaks about corporate sustainability, showing how companies can successfully navigate and manage today’s controversial societal issues, become better corporate citizens and make their businesses stronger, more relevant and more profitable.

Essam Doad provides first response mental health interventions to refugees and displaced populations.

As the first woman in the UK to be ordained in the Jewish faith, Rabbi Jackie Tabick has forged a path of inclusiveness from her work’s beginning.

Courtney E. Martin’s work has two obsessions at its core: storytelling and solutions.

In "Bad Feminist," her 2014 book of essays, Roxane Gay laid out a wise, funny and deeply empathetic vision of modern feminism, acceptance and identity -- flaws and all.

Sometimes controversial, always practical ethicist Peter Singer stirs public debate about morality, from animal welfare to global poverty.

Max Tegmark is driven by curiosity, both about how our universe works and about how we can use the science and technology we discover to help humanity flourish rather than flounder.

Ingrid Fetell Lee studies joy and reveals how we can find more of it in the world around us.

Dr. Valerie Purdie-Greenaway teaches, conducts research and consults with global leaders to help them develop and foster diverse and inclusive work.

Kathy Nicholson Hull founded the first freestanding pediatric palliative care center in the US.

Humorist, writer and trickster Emily Levine riffs on science and the human condition.

At MIT's Media Lab, Tod Machover creates boundary-breaking new music, often using new instruments and music technologies he has invented.

Magnus Larsson hopes to build new structures in the desert -- by using bacteria to turn shifting sand into a solid mass.

Sergey Brin is half of the team that founded Google.

TED Senior Fellow Andrew Pelling uses novel materials for next-generation medical innovations and speculative living technologies of the future.

Poet Ali has crafted a unique brand of impact and connection-driven, entertainment arts. The experience feels like a nonjudgmental conversation with a talented friend full of laughter, tears and steeped in some deep truth.

Joe Lassiter focuses on one of the world’s most pressing problems: developing clean, secure and carbon-neutral supplies of reliable, low-cost energy all around the world.

Don Tapscott, Executive Chairman of the Blockchain Research Institute, is one of the world’s leading authorities on the impact of technology in business and society. He has authored 16 books, including "Wikinomics: How Mass Collaboration Changes Everything," which has been translated into over 25 languages

Young spoken-word poet Malcolm London has been called the "Gil Scott-Heron of this generation" (by Cornel West). His feisty, passionate performances take on the issues of the day, including the Chicago education system in which he grew up.

A pioneer in the field of neuroeconomics, Paul Zak is uncovering how the hormone oxytocin promotes trust, and proving that love is good for business.

Sauti Sol blends warm resonant pop with traditional Kenyan influences. Their mélange of energetic rhythms has promoted the group to become one of Africa’s most celebrated.

The co-founder of Proximie, Nadine Hachach-Haram is a curious surgeon with a passion for technology and innovation -- and a desire to make a difference in the world.

Kate Bowler is reexamining her perspective on the "prosperity gospel": the belief that good things happen to good people.