Peter D. Ward describes the unique traits of our solar system that helped life to gain an initial foothold. Once life arises, it survives tenaciously. Ward explains how important is it to have a Jupiter to divert threatening swarms of comets, a large moon to provide nurturing tides, and a crust of moving plates to recycle the stuff of our world. Despite the flood of newly discovered worlds, Ward argues that our planet is more precious than we may realize.
Ward's academic career has included teaching posts and professional connections with Ohio State University, the NASA Astrobiology Institute, the University of Calgary, and the California Institute of Technology. He was elected as a Fellow of the California Academy of Sciences in 1984. Peter Ward specializes in the Cretaceous Tertiary extinction event and mass extinctions generally. He has published books on biodiversity and the fossil record. His 1992 book *On Methuselah's Trail* received a "Golden Trilobite Award" from the Paleontological Society as the best popular science book of the year. Ward is co-author, along with astronomer Donald Brownlee, of the best-selling *Rare Earth: Why Complex Life Is Uncommon in the Universe*, published in 2000. In that work, the authors suggest that the universe is fundamentally hostile to advanced life, and that, while simple life might be abundant, the likelihood of widespread lifeforms as advanced as those on Earth is marginal. According to Ward's April 2007 book, *Under a Green Sky*, all but one of the major extinction events in history have been brought on by climate change the same global warming that occurs today. The author argues that events in the past can give valuable information about the future of our planet.