Margaret A. Syverson discusses the ways in which a theory of composing situations as ecological systems might productively be applied in composition studies. She demonstrates not only how new research in cognitive science and complex systems can inform composition studies but also how composing situations can provide fruitful ground for research in cognitive science. Syverson first introduces theories of complex systems currently studied in diverse disciplines. She describes complex systems as adaptive, self-organizing, and dynamic; neither utterly chaotic nor entirely ordered, these systems exist on the boundary between order and chaos. Ecological systems are "metasystems" composed of interrelated complex systems. Writers, readers, and texts, together with their environments, constitute one kind of ecological system. Four attributes of complex systems provide a theoretical framework for this study: distribution, embodiment, emergence, and enaction. Three case studies provide evidence for the application of these concepts: an analysis of a passage from an autobiographical poem by Charles Reznikoff, a study of first-year college students writing collaboratively, and a conflict in a computer forum of social scientists during the Gulf War. The diversity of these cases tests the robustness of theories of distributed cognition and complex systems and suggests possibilities for wider application. Syverson concludes with a discussion of some implications of an ecological approach for composition research, pedagogy, and assessment, presenting the Learning Record model as one practical application of the theory. Finally she argues that technological changes have created new environmentsfor composing, providing an opportunity to reconsider conventional environments as well.