Picture books often play an important role in childhood socialization. Given the seriousness of environmental problems, we ask how natural, modified, and built environments have been portrayed in children's books. To answer this question, we analyze the 296 books receiving Caldecott awards from 1938 to 2008. Two possibilities are explored with respect to content change. Growing concern about critical environmental problems, such as decline in biodiversity and deforestation, may have led to an increase in illustrations and stories about wild animals and the natural environment. Alternatively, the increasing isolation of people from the natural world may have resulted in a decline in the perceived relevance of these environmental issues and resulted in fewer stories and depictions. Our findings support the isolation hypothesis. There have been significant declines in depictions of natural environments and animals while built environments have become much more common. These findings suggest that today's generation of children are not being socialized, at least through this source, toward an understanding and appreciation of the natural world and the place of humans within it.Because children's picture books often play an important role in socialization (e.g., Houston-Price et al. 2009), researchers have examined the contents of these books to discover how the significant issues of the time are being depicted. As Pescosolido, Grauerholz, and Milkie (1997:444) point out, ''the intended clarity and moral certainty with which adults provide children with tales of their world offer a fortuitous opportunity to examine social relations and belief systems.'' Efforts to achieve women's and civil rights and protection of the environment represent three of the most publicized and influential social movements in modern American history, and thus, numerous studies have examined portrayals of gender and ethnicity. No studies, however, have examined the way the environment has been depicted.The purpose of our study is to examine the way the environment has been portrayed in children's picture books and to discover whether this has changed over time. Two sets of events have been taking place in American