CEO, NationBuilder; Author, "The Internet is My Religion"

Photojournalist; Author, "It's What I Do"

Medical Director, The Jed Foundation

Author, "How We'll Live on Mars"

Chief Medical Officer, American Foundation for Suicide Prevention

Director, Center for Obsessive-Compulsive and Related Disorders at Columbia University

Professor emeritus of philosophy, University of Turin; ICREA Research professor of philosophy, Pompeu Fabra University

Professor emeritus of philosophy at the University of Turin and former member of the European parliament

Director, Columbia University Clinic for Anxiety and Related Disorders

Author, "Rebooting Work"

CEO, Red Hat

Comic

Environmental Attorney

Author and Poet

Author, "Healthy Brain, Happy Life"

Author, Shadow Work: The Unpaid, Unseen Jobs That Fill Your Day

Retired Navy SEAL

Medicine & Neuroscience Chair, Singularity University

Director, McKinsey Global Institute