Melinda French Gates is cochair of the Bill & Melinda Gates Foundation, where she puts into practice the idea that every life has equal value.

Economist Dilip Ratha was the first to analyze the global significance of remittances -- money sent from foreign workers to their families back home.

What makes a great school system? To find out, Andreas Schleicher administers a test to compare student performance around the world.

Cat Laine has made it her mission to find solutions to the problems that face the world’s poor, by merging innovation and the entrepreneurial spirit.

Student Ludwick Marishane invented a water-less bathing lotion and was named the 2011 Global Student Entrepreneur of the Year Award -- all because he didn't feel like taking baths.

Enrique Peñalosa is the mayor of Bogotá, Colombia. He advocates for sustainability and mobility in the cities of the future.

As a journalist reporting on China, Sheryl WuDunn saw the everyday oppression of women around the world. She and Nick Kristof wrote "Half the Sky," chronicling women's stories of horror and, especially, hope.

Marc Koska wants to improve health care in the developing world by re-designing dangerous medical tools -- and offering education to practitioners in under-funded clinics.

Jim Yong Kim is leading a global effort to end extreme poverty and promote shared prosperity.

Journalist Andrew Mwenda has spent his career fighting for free speech and economic empowerment throughout Africa. He argues that aid makes objects of the poor -- they become passive recipients of charity rather than active participants in their own economic betterment.

Shukla Bose is the founder and head of the Parikrma Humanity Foundation, a nonprofit that runs four extraordinary schools for poor children.

Jody Williams won a Nobel Peace Prize for her efforts to eradicate landmines. Now she’s teaming up with five other female peace laureates to empower women to fight violence, injustice and inequality.

Tim Jackson is a British ecological economist and professor for sustainable development at the University of Surrey. He is the author of "Prosperity without Growth" and director of the Centre for the Understanding of Sustainable Prosperity.

Ernest Madu founded the Heart Institute of the Caribbean, a revolutionary clinic for cardiovascular diseases in Kingston, Jamaica -- revolutionary for offering first-class health care in a developing nation. His next stop: Nigeria.

Sloan Scholar, Fulbright Fellow, Professor Emeritus of Neuroscience, Jim Fallon looks at the way nature and nurture intermingle to wire up the human brain.

Geopolitical futurist Parag Khanna foresees a world in which megacities, supply chains and connective technologies redraw the map away from states and borders.

Amos Winter and his team at MIT built the Leveraged Freedom Chair, a cheap lever-powered wheelchair whose design and develop put the user first.

In his legendary career in chemistry, George Whitesides has been a pioneer in microfabrication and nanoscale self-assembly. Now, he's fabbing a diagnostic lab on a chip.

Edwidge Danticat’s novels and short stories are fast becoming iconic representations of the immigrant experience -- and what it means to be Haitian-American.

Sanjit “Bunker” Roy is the founder of Barefoot College, which helps rural communities becomes self-sufficient.

Sanjay Pradhan is vice president of the World Bank Institute, helping leaders in developing countries learn skills for reform, development and good governance.

TED Senior Fellow Sonaar Luthra is measuring climate-related water risk and implementing solutions for organizations and communities facing 21st-century water security challenges.

Paul Romer's research on catch-up growth in low- and middle-income countries has emphasized the importance of government policies that encourage orderly urban expansion.

Nandan Nilekani is the author of "Imagining India," a radical re-thinking of one of the world’s great economies. The co-founder of Infosys, he helped move India into the age of IT.

Danny Dorling teaches and writes about the geography of our human world.

Atomic physicist Joshua Silver invented liquid-filled optical lenses to produce low-cost, adjustable glasses, giving sight to millions without access to an optometrist.

David Damberger’s work with Engineers Without Borders has taken him from communities in India to Southern Africa to help build infrastructure -- and learn.

BCG's Seema Bansal asks: Can governments actually make a meaningful difference in education? And rapidly? Yes, it turns out.

Ian Goldin brings fresh thinking to bear on the big, looming issues of the future.

Kang Lee has devoted his career to understanding the development of social cognition and behavior.