Steve Howard leads the sustainability effort at Ikea, helping the low-price-furniture giant to bring sustainable products to millions of people.

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?

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.

Maja Bosnic wants to make public money work better for everyone.

Joy Buolamwini's research explores the intersection of social impact technology and inclusion.

Benjamin Barber suggested that the future of the world may lie with the politicians who implement practical change every day: mayors.

As head of Instagram, Adam Mosseri leads the engineering, product, and business teams to create experiences that bring people together.

Jim Hagemann Snabe is the chairman of the world’s largest container transportation company, A.P. Møller - Mærsk, and of industrial giant Siemens. He is also a member of the board of trustees at the World Economic Forum.

As co-creator of Siri, Tom Gruber helped redefine the role of machine intelligence in our lives and transformed the way we interact with our devices.

Stacey Baker assigns photography for the wide-ranging vision of the weekly New York Times Magazine.

Donald Sadoway is working on a battery miracle -- an inexpensive, incredibly efficient, three-layered battery using “liquid metal."

Bursting forth from Canada’s capital, native producer and DJ crew A Tribe Called Red is making an impact on the global electronic scene with a truly unique sound.

Using fMRI imaging to watch the human brain at work, Nancy Kanwisher’s team has discovered cortical regions responsible for some surprisingly specific elements of cognition.

Toby Eccles has created a radical financial instrument that helps private investors contribute to solving thorny public problems.

Wendy De La Rosa uses behavioral science to help people make better financial decisions.

Former Harvard Law School Dean Martha Minow tackles the unintended effects of technology on those already impacted by discrimination and disadvantage.

Kym Loren Worthy is the prosecutor of Wayne County, Michigan, home to Detroit.

Frances Frei is a professor of technology and operations management at the Harvard Business School.

Björn Ulvaeus is a Swedish songwriter, musician, singer, guitarist, producer and a member of the musical group ABBA.

Candis Smith is on a mission to eliminate outdated, inaccurate commonsense ideas about inequality.

John Wooden, affectionately known as Coach, led UCLA to record wins that are still unmatched in the world of basketball. Throughout his long life, he shared the values and life lessons he passed to his players, emphasizing success that’s about much more than winning.

Jane Walsh is passionate about fighting for the rights of vulnerable victims in the criminal justice system.

Ellen Dunham-Jones takes an unblinking look at our underperforming suburbs -- and proposes plans for making them livable and sustainable.

Jon M. Chu makes up stories for a living -- and if the success of his film "Crazy Rich Asians" is any indication, those stories are true game-changers.

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.

Russell Foster studies sleep and its role in our lives, examining how our perception of light influences our sleep-wake rhythms.

Sylvia Earle has been at the forefront of ocean exploration for more than four decades. The winner of the 2009 TED Prize, she's a tireless advocate for our oceans.

Dambisa Moyo is an international economist who analyzes the macroeconomy and global affairs.

With photography, Yann Arthus-Bertrand has captured the beauty of the Earth. Through video and film, his latest projects bind together ecology and humanism. For him, it's all about living together.