As we enter the twenty-first century, ecological concepts have been adopted by, and adapted to, virtually every academic and applied field-from the social sciences and humanities to engineering, planning, medicine, business, and politics. With ever-increasing awareness, humanity is arriving at an understanding that we live in an ecological-and a human ecological-world.Ecology, as an interdisciplinary science, has always wrestled with topics of complexity and comprehensiveness. However, some of the most challenging issues have occurred at the intersection of natural and human ecology. For some, ecology should focus on the scientific study of nature; for others, humans are an inescapable part of the living world and the domain of ecology must include them. These concerns date to before the founding of the Ecological Society of America (ESA); indeed, they were a significant aspect of ecology from the outset.Human ecology has a complex history. The first decades of the twentieth century saw multiple attempts to initiate the field, coming not from scientific ecology, but from social sciences and human studies disciplines such as geography, sociology, anthropology, and psychology. During the 1950s and 1960s, similar attempts were made in various applied fields, including health, planning, architecture, and design. However, these initiatives seldom extended beyond their fields of origin, and they rarely had any relation to one another. ESA produced multiple advocates for human ecological orientations over the years, along with many attempts to establish formal organizational structures-though these efforts tended to be periodic and not sustained (see Cittadino, 1993; Young, 1974 Young, , 1983.In the 1970s and 1980s, a truly interdisciplinary human ecology began to emerge, stimulated in part by the advent of the environmental movement and by the founding of an assortment of academic degree programs in human ecology worldwide.