Past educational improvement endeavors were fundamentally centered on the learner as an individual. This changed by the early 1990s after an increasing number of educators and researchers embraced sociocultural learning concepts such as "communities of practice," "communities of learners," and "knowledge-building communities." These ideas are originally grounded in a dialectical materialist, cultural-historical theory of activity, or, as Lev Vygotsky called it, in a "concrete human [social] psychology." However, as these concepts filtered into Western scholarship, some of their defining characteristics have been lost or downplayed. The intention of this article is thus to offer a more complete theorization of the educational notion of "community" that is centered on collective activity or practice mediated by history and culture/society. Two case studies, which exemplify learning communities using this lens, conclude the paper. (Contains 2 figures and 1 table.)