When this book came out in 1990 it weighed seven and a half pounds. And I like to refer to it as a magnum opus. A magnum opus being defined as a work so heavy that when dropped from a three story building it can kill a man. Well at any rate, it certainly made the field accessible to a younger generation of researchers who were coming on. And I'd like to think has greatly stimulated research in many, many of those areas.

And it had the unique distinction in 1991 of receiving the non-fiction Pulitzer Prize which is the only time, I think ever... it's one of the very few times that any book on science or about science has gotten a Pulitzer. And this was the only time that it was... when a book written primarily for scientists and naturalists, primarily, not for the broad audience, received that distinction. So it was well done and I think that had we tried to come together even two or three years afterwards to write that book it would have been too late. It was... just things had gone too far, we'd forgotten too much. So it was certainly a great moment to bring together 20 years of close collaboration. It's a rare opportunity, I think, to be able to work closely with someone as gifted as Bert Hölldobler and whose talents and interest and training was so complimentary to mine. He'd been trained in... very substantially in the German tradition of experimental work.  He'd done lots of field work himself. But he had this distinctive Germanic analytic techniques which was brought to bear.  And of course I had the natural history, the ecology background, evolutionary biology. So we brought those things together, it worked out very well.