Book excerpt: For more than a million years, man's utter dependence on technology has been producing a host of intricate problems. For example, we steadily reduce the need for human labor while finding ways to increase life expectancy. We mass produce the automobile without grasping the harsh effects it leaves on the environment. The Human Legacy concerns the evolution and development of man–physically, socially, psychologically–into the latest version of the species we see around us today. The author paints an intriguing picture of man, living in complex societies and trying to solve the unanticipated consequences of action.