Abstract: There are three components to boundary objects as outlined in the original 1989 article. Interpretive flexibility, the structure of informatic and work process needs and arrangements, and, finally, the dynamic between illstructured and more tailored uses of the objects. Much of the use of the concept has concentrated on the aspect of interpretive flexibility and has often mistaken or conflated this flexibility with the process of tacking back-and-forth between the ill-structured and well-structured aspects of the arrangements. Boundary objects are not useful at just any level of scale or without full consideration of the entire model. The article discusses these aspects of the architecture of boundary objects and includes a discussion of one of the ways that boundary objects appeared as a concept in earlier work done by Star. It concludes with methodological considerations about how to study the system of boundary objects and infrastructure.