Using the trope of an extended discussion among characters from different professional backgrounds, Jacobs sets out to examine the moral codes that govern work. She finds two "syndromes"--two mutually exclusive collections of connect- ed traits, self-organized systems that have evolved over the long span of human history. They derive, she argues, from the two and only two ways humans as a species have of making a living: taking and trading. (Most animals have only taking, better known as hunting and gathering.) She dubs them the "guardian syndrome" and the "commercial syndrome."