What Are You Optimistic About? John Brockman, Mihaly Csikszentmihalyi, Brian Greene, Jared Diamond, Steven Pinker, John Horgan, John McCarthy, Sam Harris, Chris Anderson, Martin Rees, Carlo Rovelli, Daniel C. Dennett, Andrew Brown, Richard Dawkins, Michael Shermer, Clay Shirky, J. Craig Venter, Douglas Rushkoff, Anton Zeilinger, Leonard Susskind, Geoffrey Miller, Marcelo Gleiser, Martin E. P. Seligman, Freeman J. Dyson, Jerry Adler, Gino Segrè, Lawrence Maxwell Krauss, Robert Shapiro, Frank Wilczek, Paul J. Steinhardt, Lee Smolin, Lisa Randall, Charles Seife, Karl Sabbagh, Alexander Vilenkin, Max Tegmark