This casual and lively book deals with some of the most basic philosophical questions we have: why are we here? How did life arise from nonliving particles? What is the fate of the earth? Sagan (What Is Life?
), son of astronomer and science writer Carl Sagan, draws on, among others, science, philosophy and “the speculations of science fiction” in attempting to answer these questions. He begins with a quick introduction to James Lovelock's Gaia hypothesis, that the Earth is a living, self-regulating organism, and that life is not just a “passenger” on Earth but an integral part of the planet's systems. In chapters titled “Earth,” “Water,” “Air” and “Fire,” Sagan touches on the oceans and atmosphere, the evolution of life on Earth, the laws of thermodynamics and human consciousness, always circling back to Lovelock's theories. Sagan is equally comfortable discussing scientists like Richard Dawkins and Lewis Thomas, and science fiction authors like Philip K. Dick and A.E. van Vogt. The chatty style and ranging mind communicate a broad understanding and should appeal to inquisitive readers who want to know more about Earth and our relationship with it. (Sept.)
