Bringing cross-disciplinary tactics and innovation to a moribund defense industry, N Square’s Erika Gregory seeks to wean the world from its nuclear stockpiles.

Kirk Sorensen stumbled across thorium while doing research on how to power a lunar community. Thorium is a cleaner, safer, and more abundant nuclear fuel -- one that Kirk believes will revolutionize how we produce our energy.

Holly Morris tells the stories of women around the world through documentary, television, print and the web.

Michael Shellenberger is a global thinker on energy, technology and the environment.

Emma Belcher develops and implements strategy for reducing the threat posed by nuclear weapons.

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.

Isabelle Boemeke is the world's first nuclear energy influencer.

Ralph Langner is a German control system security consultant. He has received worldwide recognition for his analysis of the Stuxnet malware.

At 14, Taylor Wilson became the youngest person to achieve fusion -- with a reactor born in his garage. Now he wants to save our seaports from nuclear terror.

Marilyn Waring advocates for a public policy database that recognizes all unpaid work -- and the preservation of ecosystems -- instead of relying on GDP.

Naomi Shah won the 2011 Google Science Fair in the age 15-16 category.

Deborah Rhodes is an expert at managing breast-cancer risk. The director of the Mayo Clinic’s Executive Health Program is now testing a gamma camera that can see tumors that get missed by mammography.

William Ury is a mediator, writer and speaker, working with conflicts ranging from family feuds to boardroom battles to ethnic wars. He's the author of "Getting to Yes."

Scilla Elworthy founded Oxford Research Group in 1982, to promote effective dialogue between nuclear weapons policy-makers and their opponents.

Dan Berkenstock and his team at Skybox Imaging are rethinking how to take photographs from space.

BCG's Antoine Gourévitch is a senior partner in the firm's Paris office.

John F. Kerry is the United States's first Special Presidential Envoy for Climate.

Diana Adams is a leading international lawyer and activist for underserved families.

Geraldine Hamilton builds organs and body parts on a chip -- to test new, custom cures.

As computer access expands, Mikko Hypponen asks: What's the next killer virus, and will the world be able to cope with it? And also: How can we protect digital privacy in the age of government surveillance?

Robin Murphy researches robots -- ground, aerial and marine -- that can help out during disasters.

Stuart Russell wrote the standard text on AI; now he thinks deeply on AI's future -- and the future of us humans, too.

Graham Allison is a leading analyst of US national security and defense policy with a special interest in China, nuclear weapons and decision-making.

On more than 120 deep-sea expeditions, Robert Ballard has made many major natural discoveries, such as the deep-sea vents. Oh, and he found the Titanic.

Paul Gilding is an independent writer, activist and adviser on a sustainable economy. Click through to watch the onstage debate that followed this talk.

In telling stories of technologies and the individuals who created them, George Dyson takes a clear-eyed view of our scientific past -- while illuminating what lies ahead.

BCG's Matt Langione is a partner in the firm's Boston office, where he brings research-intensive deep tech innovations to market.

Ben Kacyra uses state-of-the-art technology to preserve cultural heritage sites and let us in on their secrets in a way never before possible.

Margaret Levi is committed to promoting equity and equality by ensuring that political, economic and social arrangements enable the flourishing of all.

Severn Cullis-Suzuki is a lifelong environmental activist seeking justice for future generations.