What would you say are the greatest scientific ideas that mankind has discovered? Most of us chemists would say that the notion that matter consists of atoms would have to be one of them, and physical chemist Peter Atkins does not disappoint us on that score. He also treads ground familiar to us when he describes entropy and energy, and evolution and DNA. However, even his remarks about these topics are worth reading, because he demonstrates how important scientific ideas can be explained to an interested layperson. One of the other subjects in his "Top Ten" list sounds as if it might be a topic in a chemistry course, but he brings a broader perspective to "Symmetry" than that, including the gauge symmetries of forces and particles. Another of the great ideas of science has to be the quantum theory (Chapter Seven), for which Symmetry makes a nice introduction. Atkins finishes with two excellent chapters on Cosmology and Spacetime, and what I thought was the most surprising choice, a chapter on Arithmetic: The Limits of Reason. Teachers of chemistry and other sciences will likely have their horizons extended by Galileo's Finger. A longer review of this book will appear soon in the printed Journal of Chemical Education.