Life history theory has revolutionized the study of the evolved life course both across and within species. Humans are no exception. Life history theory provides nuance to claims of human uniqueness in the tree of life, including among mammals, and among primates in particular. This chapter first explains how life history theory delivers optimal trait characteristics given trade-offs that are defined by costs and benefits of different “solutions” to fitness-relevant problems. It reviews the current understanding of the evolution of the human life course, and the chapter evaluates explanations of long postreproductive life spans in human populations. It then provides a framework for modeling how selection pressures in different socioecological settings could shape the flexible expression of demographic, physiological, and even psychological traits in our species. Special emphasis is placed on the role that exogenous mortality and environmental unpredictability (and their cues) play on shaping a number of behavioral and physiological traits related to survival. Claims certainly outpace definitive tests, but after a half century, since life history theory was first introduced to the human life sciences, promising new directions are expanding the breadth of topics covered beyond demography, using multiple methods and spanning diverse disciplines.