Abstract
Every budding geology student early learns the maxim that the present is the key to the past. Doug Macdougall, professor emeritus of earth sciences at Scripps Institution of Oceanography, would certainly concur with that adage. He has written Why Geology Matters in part because of a "desire to share some of the excitement about what geoscientists have learned about our amazing planet in recent decades" (p. xiv); much of what we have learned does indeed concern the geologic past. The primary thrust of Macdougall's book, however, is that the geologic past is also a key to the geologic future. As he sees things, the Earth sciences hold "the keys to understanding and addressing many of the most pressing problems facing society" (p. 250).