books.google.com - The sweeping diversity of complex life on Earth, Ward and Brownlee argue, evolved out of an extraordinary set of physical conditions and chance events that would be extremely hard to duplicate––though not impossible. Many planets throughout the vastness of the Universe may be teeming with microbial...http://books.google.com/books/about/Rare_Earth.html?id=qz7YBLkabzAC&utm_source=gb-gplus-shareRare Earth
