Quick to lose interest if a site failed to spark his restless imagination, he would often donate the land to a university or professional organization for them to pursue the dig on their own. A great deal of useful data and many Stone Age materials that now resided in museums had come from his generosity. One of his main beneficiaries through the years had been the Chicago-based Horizon Foundation for Anthropological Research, the highly respected organization with which Gideon had had a long informal association. It was this foundation that was sponsoring the dinner in his honor.

Gunderson’s unsophisticated theoretical spoutings, while always politely received by his fellow archaeologists (everyone wanted to stay on his good side; you never knew when the next donated site was coming), were privately regarded as naive, erratic, and generally half baked. His specialty was the Neanderthals, who had always been a focal point for dispute among paleoanthropologists. Until the 1990s the fight had been over whether or not we humans were directly descended from them. Gunderson had been at the forefront of those who believed we were.

But in the 1990s the DNA scientists, having found a way to extract mitochondrial DNA from prehistoric skeletons, had pretty well resolved the matter.

We weren’t.

The ground shifted. Now the question became whether humans – Homo sapiens – and Neanderthals – Homo neanderthalensis – had interbred at all, or were distinctly separate species that did not – could not – interbreed. Gunderson put down one cudgel and picked up another. Handsome, silver haired, and articulate (“a combination of Alistair Cooke and Walter Cronkite,” as one TV magazine put it) he became one of the most publicly visible proponents of “admixture theory” – that is, the theory that Neanderthals and humans had intermittently interbred during the four or five thousand years that they coexisted in Europe before the Neanderthals died out altogether about 24,000 years ago.