Luvvie Ajayi Jones is a two-time New York Times bestselling author, podcast host and sought-after speaker who thrives at the intersection of humor, media and justice.

A professor and entertainer, Dannagal G. Young studies the impact of modern media on social and political discourse -- and delivers her findings in unexpectedly performative ways.

Dr. Leana Wen is Baltimore City's Health Commissioner.

Philip K. Howard is the founder of Common Good, a drive to overhaul the US legal system. His new book is "Try Common Sense."

Ingrid Betancourt was a presidential candidate in Colombia in 2002 when she was kidnapped by guerilla rebels. After six years in captivity and a high-profile rescue, she now writes about what she learned about fear, forgiveness and the divine.

The author of "The Perfect Storm" and the director of the documentaries "Restrepo" and "Korengal," Sebastian Junger tells non-fiction stories with grit and emotion.

Known for her compassionate work with the terminally ill, Joan Halifax is a driving force of socially engaged Buddhism.

Bruce Schneier thinks hard about security -- as a computer security guru, and as a philosopher of the larger notion of making a safer world.

Writer, producer and free-speech champion Norman Lear defined decades of US popular culture with his groundbreaking TV shows.

Srishti Bakshi works to address gender-based violence by increasing mobility options for women.

Elizabeth Zion is an 18-year-old writer, poet and student from Dublin, Ireland.

Sophal Ear leads research on post-conflict countries -- looking at the effectiveness of foreign aid and the challenge of development in places like his native land, Cambodia.

Matthew Broadhurst is an ear, nose and throat surgeon based in Brisbane, Australia.

Lee Mokobe is a 20-year-old South African slam poet and co-founder of Vocal Revolutionaries.

Iraqi-born Zainab Salbi founded and runs Women for Women International, and has dedicated her life to helping women in war-torn regions rebuild their lives and communities.

Aziz Abu Sarah helps people break down cultural and historical barriers through tourism.

Chad Frischmann is working to get humanity to "drawdown," the point in time when the concentration of atmospheric greenhouse gases begins to decline on a year-to-year basis.

Thomas Suarez, a 12 year old, taught himself to build iphone apps.

A branding expert and one of the leading authorities on business communication, Alan Siegel wants to put plain English into legal documents for government and business.

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

Peachy Liv is an 18-year-old activist and content creator from Indonesia.

Frank Warren is the creator of the PostSecret Project, a blog full of secrets anonymously shared via postcard.

Teresa Bejan writes about political theory, bringing historical perspectives to bear on contemporary questions.

Neil Harbisson's "eyeborg" allows him to hear colors, even those beyond the range of sight.

Daniel Suarez concocts thrilling reads from terrifying (and not-so-farfetched) near-future scenarios.

Zeresenay "Zeray" Alemseged digs in the Ethiopian desert, looking for the earliest signs of humanity. His most exciting find: the 3.3-million-year-old bones of Selam, a 3-year-old hominid child, from the species Australopithecus afarensis.

Jamais Cascio follows the threads of civilization's intended (and unintended) consequences into an unpredictable future, bringing back glimpses of a green world wired beyond our wildest dreams.

Rodney Mullen is a legendary skateboarder who transformed the art of street skating.

Ji-Hae Park spreads the joy of classical to music to those who might not otherwise hear it -- and in the process shows that you can rock out on the violin.

Feras Fayyad's films bear witness to the struggles of his fellow Syrians, as they struggle to survive and save their neighbors.