Reading Elizabeth Kolbert's haunting The Sixth Extinction was difficult but enlightening. She presents what most people fear facing but is happening around us. We are causing the loss of almost unbelievably large parts of the natural world on which we rely without realizing it---sleepwalking, I would say. Her writing in the New Yorker covers more issues most people are too uncomfortable to learn about: overpopulation, the limits of technology to solve the problems most people think technology will solve, and the like. She presents the issues simply and directly, forcing you to draw your conclusions. I considered it critical to bring a guest so thoughtful and knowledgeable about relevant issues she saw firsthand. Her perspective is difficult to face, but the alternative of putting your head in the sand prevents you from solving the problems.