Neil deGrasse Tyson talked about his book Death by Black Hole: And Other Cosmic Quandaries, published by W.W. Norton. It is a collection of essays about the cosmos. Topics included astrophysics, 'killer asteroids,' ionizing radiation, X-rays and microwaves, and habitable zones. After his presentation he responded to audience members' questions. Mr. Tyson became director of the Hayden Planetarium in 1996. He is the author of several books, including Origins: Fourteen Billion Years of Cosmic Evolution (with Donald Goldsmith) and The Sky Is Not the Limit: Adventures of an Urban Astrophysicist.