The fascinating story of a problem that perplexed mathematicians for nearly 400 yearsIn 1611, Johannes Kepler proposed that the best way to pack spheres as densely as possible was to pile them up in the same way that grocers stack oranges or tomatoes. This proposition, known as Kepler's Conjecture, seemed obvious to everyone except mathematicians, who seldom take anyone's word for anything. In the tradition of Fermat's Enigma, George Szpiro shows how the problem engaged and stymied many men of genius over the centuries--Sir Walter Raleigh, astronomer Tycho Brahe, Sir Isaac Newton, mathematicians C. F. Gauss and David Hilbert, and R. Buckminster Fuller, to name a few--until Thomas Hales of the University of Michigan submitted what seems to be a definitive proof in 1998.George G. Szpiro (Jerusalem, Israel) is a mathematician turned journalist. He is currently the Israel correspondent for the Swiss daily Neue Zurcher Zeitung.