This book argues that the central assumption of immunology—that we survive through the recognition and elimination of non-self—has become a defining concept of the modern age. Tracing this immunological understanding of self and other through an incredibly diverse array of venues, from medical research to legal and military strategies and the electronic revolution, the author shows how this defensive way of looking at the world not only destroys diversity but also eliminates the possibility of truly engaging difference, thereby impoverishing our culture and foreclosing tremendous opportunities for personal growth. To illustrate these destructive consequences, he likens the current craze for embracing diversity and the use of politically correct speech to a cultural potluck to which we each bring different dishes, but at which no one can eat unless they abide by the same rules. Similarly, loaning money to developing nations serves as a tool both to make the peoples in those nations more like us and to maintain them in the nonthreatening status of distant dependents. To break free of the resulting downward spiral of homogenization and self-focus, the author suggests that we instead adopt a new defining concept based on embryology, in which development and self-growth take place through a process of incorporation and transformation. In this effort he suggests that we have much to learn from non-Western peoples, such as the Balinese, whose ritual practices require them to take on the considerable risk of injecting into their selves the potential dangers of otherness—and in so doing ultimately strengthen themselves as well as their society.