In Japan, the beauty of leaves in autumn is revered with almost religious fervor. Part of the autumn weather forecast is devoted to showing the "leaf front" as the color change in trees moves across the country. Millions of tourists travel to marvel at the display.

But how many people ask themselves why trees put on such a spectacular display? Probably not many.

It took a man of uncommon intellect to ask the question no one else had thought of -- William Hamilton, the Oxford evolutionary biologist who died last year. Hamilton was arguably the most important biologist since Darwin, and his work forms the basis for much of modern evolutionary biology. But his ideas about autumn colors remained just rumors in the zoological community until earlier this year, when they were posthumously published. Co-author Sam Brown, now of the University of Montpellier, France, had been working on the paper when Hamilton died.