I wrote an essay "On Aggression" for Big Questions in Science, which was published in hardback by Jonathan Cape in October 2002 and in paperback by Vintage a year later. The book was quite successful and was translated into several languages. (Please note that, contrary to the rather embarrassing impression given by the blurb on Amazon, myself and several of the other contributors were not "leading scientific thinkers". The book was a collaboration between leading scientists and journalists.)