Cosmos is the book version of Carl Sagan's famous television series of the same name. While it certainly is about Sagan's field of expertise, astronomy, it also a survey of the intellectual history of mankind. Sagan shows us that not only did ancient Greek mathematicians know that the earth is a sphere, with the work of Eratosthenes in the third century B.C., they even knew its circumference - and Sagan allows his readers to easily appreciate both the logic and the calculations involved. A page or two later readers are introduced to the existence of the wondrous ancient "Library at Alexandria," a university-like complex in Egypt "where we humans first collected, seriously and systematically, the knowledge of the world...." As the pages and chapters fly by, we are treated to Kepler, Copernicus, and Galileo; to Apollo missions, time dilation, Mars landers, and Arecibo. And tantalizing readers throughout is one of the greatest questions that we can ever ask - Are we alone? Or is our universe rich with life?