The Nemesis Affair: A Story of the Dealth of Dinosaurs and the Ways of Science is a fascinating book by David M. Raup a statistical anthropologist from the University of Chicago. Raup teaches the reader about Nemesis, a companion star to our Sun that returns and closes on the Solar System once every 26 million years. When it approaches, it has effects on the Sun's Oort clouds and in turn disrupts the paths of associated comets, sending some hurling toward Earth. This is a very interesting theory that attempts to explain the repetitive nature of mass extinctions in the history of our planet (five major events the last of which occured at the end of the Cretaceous period and led to the demise of the dinosaurs). This is a fascinating read by a brilliant man and writer. If you're interested in astronomy or palentology, you'll enjoy this book.