George Ayittey

Economist, Authority on the development of Africa, Author

Dennis Avery

Former Director, Center for Global Food Issues at the Hudson Institute

Anthony Atala

Director, Wake Forest Institute for Regenerative Medicine

Karen Armstrong

Founder of The Charter for Compassion

John Amatt

Mountaineer, Founder & President of One Step Beyond WorldWide

Ted Allen

Host, "Chopped," Contributor, "The Best Thing I Ever Ate"

Jeff Allen

Stand-up Christian Comedian; Marriage Motivator

Debbie Allen

Creative Marketing Expert & Business Speaker

Alan Alda

Actor; Writer; Science Advocate; Director

David Agus

Co-Founder of Navigenics, Author of "The End of Illness" & Host of "The Checkup with Dr. David Agus"; Professor of Medicine & Engineering at the University of Southern California

The Book of Animal Secrets

Patch Adams

Physician & Clown; Founder of Gesundheit Institute; Inspiration for the Robin Williams Movie "Patch Adams"

Mike Abrashoff

Leadership Speaker, Former Commander of USS Benfold & Author of "It's Your Ship"

Marc Abrahams

Creator of the Ig Nobel Prizes

Jim Abbott

Former One-Handed Major League Baseball Pitcher