This exploration of the roots of violence in human society finds a villain in biology: not in the genetic urge that drives each organism to reproduce, but in the forces that create larger "superorganisms" that seek to perpetuate themselves. Bloom (whose credentials range from cancer research at Roswell Park Memorial Cancer Research Institute to experimental graphics, programmed learning, and founding a public relations firm that represented many well-known rock artists) draws on an impressive range of historical, anthropological, and biological research to support his thesis. (The 333 pages of text are followed by an additional 117 pages of notes and bibliography.) From this massive body of material, he arrives at a conclusion that such philosophers as Hobbes would find congenial: Aggression is not an aberrant force in society, but its very foundation. From Caesar to Khomeini, Bloom finds that those who have lead great nations are propagators of memes--the core bodies of a culture's key ideas that are the ideological equivalent of genes. History is not so much the contest of armies as of memes, and a strong meme drives out the weak as surely as the genes of an alpha male in a chimpanzee herd dominate those of his lesser competitors. While Bloom often gives cogent analyses of the currents of history, his thesis has an unfortunate potential for being warped to the service of chauvinism and racism. His attempts to draw lessons for the future (with comments on the predatory nature of Muslim society or the inability of African nations to transcend their tribal memes) are dubious at best, and potentially inflammatory at worst. And his ideas are often developed more by example than by exploration of their deeper consequences. Bloom's basic thesis is thought-provoking and often full of valuable insight; it is unfortunate that the implications he derives from it are so likely to encourage the worst aspects of human nature to come to the fore.