JOHN D. BARROW, a physicist, is Professor of Mathematical Science, Director of the Millennium Mathematics Project, University of Cambridge, and Gresham Professor of Geometry.

He is the author of *The World Within the World*, *Pi in the Sky*, *Theories of Everything, **The Origin of the Universe *(Science Masters Series),*The Left Hand of Creation*, *The Artful Universe*, *Impossibility: The Limits of Science and the Science of Limits; **Between Inner Space and Outer Space**;* and* The Constants of Nature: From Alpha to Omega—the Numbers That Encode the Deepest Secrets of the Universe:*and*The Constants of Nature: From Alpha to Omega.*