This article argues that understandings of work learning within human resource development (HRD) theory can be fruitfully enriched by more fully incorporating practice-based perspectives. Three contemporary theories that analyze learning as a relation of individuals with and/or in activity are discussed: the participational perspective of situated cognition, the notion of expansion from cultural-historical activity theory, and the constructs of translation and mobilization presented by actor-network theory. These are not new to HRD, but this brings them together with published empirical workplace research, employing their constructs to highlight selected dynamics that may be useful tools for HRD theory development. One element in particular is read across the three theories: the dialectic of "flying" and "grounding," or lines of discontinuity and continuity characterising work-learning. The argument is theory driven, drawing from HRD literature of work-learning and practice-based theories of social activity and knowledge production.