This paper develops a theory of layered collaboration in the development of community-based Free and Open Source Software (FLOSS). The theory is developed through a research arc of discovery (participant observation), replication (two archival case studies) and formalization (a model of developer choices). The theory explains two key findings: the overwhelming majority of work is accomplished with only a single programmer working on a task and when tasks appear too large for an individual they are more likely to be deferred until they are easier than be undertaken through structured teamwork. It is theorized that this way of organizing is successful because it fits with the motivations of the participants, the key technologies of FLOSS collaboration and the nature of software as an IT artifact. The theory, and the empirical findings in which it is grounded, are important because they enable a systematic approach to understanding the implications of FLOSS development as a model for adaptation and the future of informationalized work. Accordingly, the discussion enumerates the conditions under which this theory of organizing is likely to be successful, many stemming directly from software—an IT artifact—as an object, rather than just a facilitator, of collaboration. These are used as a framework to analyze efforts to adapt the FLOSS model of organizing for self-organizing, virtual teams in other domains of work.