Both a surgeon and a self-experimenter, Peter Attia hopes to ease the diabetes epidemic by challenging what we think we know and improving the scientific rigor in nutrition and obesity research.

Dee Boersma considers penguins ocean sentinels, helping us understand the effects of pollution, overfishing and climate change on the marine environment.

Karen J. Meech is an astronomer who investigates how habitable worlds form and explores the bigger picture of whether there is life elsewhere.

Malian singer Rokia Traore blends the traditions of her Bamana heritage with a modern singer-songwriter's approach to music-making.

Emily Nagoski teaches women to live with confidence and joy inside their bodies.

Jessica Jackley is the co-founder of Kiva.org, an online community that helps individuals loan small amounts of money, called microloans, to entrepreneurs throughout the world.

In his long career as a religious evangelist, the Rev. Billy Graham spoken to millions around the world and served as advisor to US presidents.

Using literature as a lifeline, Shaka Senghor escaped a cycle of prison and desperation. Now his story kindles hope in those who have little.

Lawrence Lessig has already transformed intellectual-property law with his Creative Commons innovation. Now he's focused on an even bigger problem: The US' broken political system.

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

Jill Sobule isn't just another singer-songwriter with catchy tunes and smart lyrics, she's one of the more insightful satirists of our age. Each of her fanciful songs captures an issue or irony, an emotion or epiphany that helps us understand what it's like to live now.

Joe Sabia investigates new ways to tell stories -- meshing viral video and new display technologies with old-fashioned narrative.

Fredy Peccerelli works with families whose loved ones “disappeared” in the 36-year armed conflict in Guatemala. The executive director of the Guatemalan Forensic Anthropology Foundation, he helps locate bodies and give back identities to those buried in mass graves.

Graphic designer

Paul Knoepfler is a biomedical scientist and writer focusing on stem cells and genetics.

Denis Dutton was a philosophy professor and the editor of Arts & Letters Daily. In his book The Art Instinct, he suggested that humans are hard-wired to seek beauty.

Dr. Kakenya Ntaiya is the founder and president of Kakenya's Dream, an international nonprofit organization leveraging education to empower girls, end harmful traditional practices and transform communities in rural Kenya.

Infrastructure Development Consultant

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

Jia Jiang's journey through rejection revealed a world hidden in plain sight, where people are much kinder than we imagine.

Jane Fonda has had four extraordinary careers (so far): Oscar-winning actor, author, fitness guru and impassioned activist.

Through his charity HALT, Jeremy Forbes aims to break through the stigma attached to mental health, raise awareness through education and empower men to open up conversations around mental health and suicide prevention.

Carol Fishman Cohen documents successful transitions back into the workforce after career breaks.

Nadia Lopez is the founding principal of Mott Hall Bridges Academy, where she is showing the world how underprivileged communities can beat the odds and create positive institutions that have a global impact.

International education entrepreneur

Dr. Chris Nowinski is leading a global conversation on concussions, CTE and the future of sports.

Andrew Marantz writes narrative journalism about politics, the internet and the way we understand our world.

Mehret Mandefro is an award-winning producer, writer and director.

When Jason B. Rosenthal's wife died, he says: "as clichéd as it sounds, I started working on living each day as it comes, to get through the complexities of life."