Roger Stein wants to bring financial engineering to the world of drug funding.

Sydney Jensen wants to shine a light on the emotional and mental impact of teaching students who have experienced trauma.

At Novalia, Kate Stone and her team use ordinary printing presses to manufacture interactive electronics, which combine touch-sensitive ink technology and printed circuits into unique and cost-effective products.

Despite an attack on his daughter Malala in 2012, Ziauddin Yousafzai continues his fight to educate children in the developing world.

Engineer and daredevil cave explorer Bill Stone is obsessed with discovery -- on Earth and beyond.

Greg Stone was a key driver in the establishment of the Phoenix Island Protected Area in the island nation of Kiribati. The second-largest marine protected area in the world -- and one of the most pristine -- PIPA is a laboratory for exploring and monitoring the recovery of coral reefs from bleaching events.

Florida-based photographer Mac Stone specializes in documenting the Everglades, an area he prizes for its wildlife and flora.

Sydney Chaffee believes that teachers and students can change the world together.

Meklit Hadero is an Ethiopian-American singer-songwriter living the cultural in-between, both in her own luminous compositions and as a co-founder of the Nile Project.

Bob Stein has long been in the vanguard: immersed in radical politics as a young man, he grew into one of the founding fathers of new media. He’s wondering what sorts of new rituals and traditions might emerge as society expands to include increasing numbers of people in their eighties and nineties.

Kevin Stone's clinic treats joint injury using the latest in bio-medicine: reconstructing damaged tissue, even replacing whole joint parts, with lab-grown cartilage and ligament.

Erica Stone works at the intersection of writing, teaching, and community organizing.

Makhtoum Abdalla is passionate about equal access to quality education for all children and young people.

Zachariah Mampilly is an expert on the politics of both violent and non-violent resistance.

Robyn Stein DeLuca asks, What do we really know about PMS?

Giles Duley began his career as a fashion photographer. When it was time for a change he found himself on a journey of war and hardship.

Paul Conneally is the public communications manager for the International Federation of the Red Cross and Red Crescent Societies, and a leader in using digital technologies for humanitarian aid.

Paula Stone Williams is a Pastoral Counselor and internationally known speaker on gender equity, LGBTQ advocacy, and religious tolerance.

At Glasswing International, Celina de Sola works to address the root causes and consequences of poverty and violence.

Writing is only his day job: Dave Eggers moonlights as a publisher, philanthropist and advocate for students and teachers.

Mick Ebeling founded the Not Impossible Foundation, a nonprofit that develops creative solutions to real-world problems.

Yassmin Abdel-Magied wears many hats, including a hijab. She's a mechanical engineer, writer and activist who campaigns for tolerance and diversity.

Photojournalist James Nachtwey is considered by many to be the greatest war photographer of recent decades. He has covered conflicts and major social issues in more than 30 countries.

Stefan Wolff studies contemporary conflicts, focusing on the prevention and settlement of ethnic conflicts and in postconflict reconstruction in deeply divided and war-torn societies.

Monika Bulaj’s stunning, painting-like photographs blur religious and cultural divisions, exploding stereotypes. She is a TED Fellow.

Samantha Nutt envisions a world where no child knows war.

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.

Rahwa Ghirmatzion is executive director of People United for Sustainable Housing, a membership-based community organization committed to social and climate justice.

Philippa Neave is senior advisor on the UN's Lexicon of Electoral Terminology.

Susan Colantuono is the CEO and founder of Leading Women.