Paul Root Wolpe examines the ethical implications of new science -- genetic modification, neuroscience and other breakthroughs that stretch our current philosophy to the breaking point. He's the chief bioethicist at NASA, among other appointments.

Stephen Coleman studies applied ethics, particularly the ethics of military and police force, and their application to human rights.

Kelly Richmond Pope researches organizational misconduct, ethics and fraud.

Over the past 35 years Peter Saul has been intimately involved in the dying process for over 4,000 patients. He is passionate about improving the ways we die.

Sometimes controversial, always practical ethicist Peter Singer stirs public debate about morality, from animal welfare to global poverty.

Kwame Anthony Appiah is a philosopher, cultural theorist and novelist. His latest book is "The Honor Code," exploring moral revolutions.

Jonathan Marks works at the intersections of ethics, law and policy -- writing and speaking about torture, obesity, fracking, health care and other pressing issues of our time.

Based in Bulgaria, Steve Keil creates companies around big social and environmental goals.

Philosopher Thomas Pogge wants to ensure medications get to those who need it most. He has published on a wide range of subjects such as global justice and human rights.

Jennifer Doudna was part of inventing a potentially world-changing genetic technology: the gene editing technology CRISPR-Cas9.

Kate Darling investigates the relationship between humans and robots -- now, and in the future.

Think of Surya Mattu as a data detective. As he writes: "I am interested in figuring out the ways in which algorithmic systems harm people."

Alice Dreger studies history and anatomy, and acts as a patient advocate.

Rodrigo Canales wants to understand how individuals influence organizations or systems--even those as complex as the Mexican drug cartels.

Michael Patrick Lynch examines truth, democracy, public discourse and the ethics of technology in the age of big data.

Ronald Sullivan is a leading theorist in the areas of criminal law, criminal procedure, trial practice and techniques, legal ethics and race theory.

Britt Wray's work is about life and what we make of it: past, present and future.

Veerle Provoost studies genetic and social parenthood in the context of donor conception.

Kriti Sharma creates AI technology to help address some of the toughest social challenges of our time -- from domestic violence to sexual health and inequality.

Iyad Rahwan's work lies at the intersection of the computer and social sciences, with a focus on collective intelligence, large-scale cooperation and the social aspects of artificial intelligence.

Dr. Gregory Stock's levelheaded look at the hotpoints where tech and ethics connect (or short circuit) have made him a popular guest on TV and radio. He directs the Program on Science, Technology, and Society at UCLA.

William Black is a professor of economics and law at University of Missouri, Kansas City.

Britain's former prime minister Gordon Brown played a key role in shaping the G20 nations' response to the world's financial crisis, and was a powerful advocate for a coordinated global response to problems such as climate change, poverty and social justice.

Ian Goldin is director of the Oxford Martin School. Through the school's program of research, collaboration and education, he's powering new, cross-disciplinary thinking about global problems from the near and far future.

Krista Tippett hosts the national public radio program "On Being," which takes up the great, animating questions of human life: What does it mean to be human? And how do we want to live?

Travis Rieder wants to help find a solution to America’s opioid crisis -- and if that sounds a bit too lofty, he’d settle for making clear, incremental progress in a responsible, evidence-based way.

Professor Sajay Samuel's proposal to reduce the burden of student loans is part of his larger preoccupation with thinking beyond the conventional categories of economics and ecology.

In our era of the patient-as-data-point, Abraham Verghese believes in the old-fashioned physical exam, the bedside chat, the power of informed observation.

Sarah Corbett does activism in a quiet, humble and intriguing way using handicrafts.

Barton Seaver is an advocate of sustainable seafood and a chef in Washington DC. His work tells the story of our common resources through the communion we all share – dinner.