This paper discusses some fundamental ideas of situated learning, activity theory, cross-contextual learning and a new field of situational boundary work. Firstly, I take up five questions or misunderstandings often had about situated learning theory and respond to these: 1) does it deny mental processing?, 2) does it consider that external circumstances determine learning?, 3) does it regard internalization of knowledge in a situation as learning?, 4) which does it focus on, individual transformation in a situation or whole collective transformation?, 5) does it consider that transfer doesn't occur? Secondly, I discuss cross-contextual learning or boundary crossing, a main subject in recent activity theory. Thirdly, I interrogate organization or states of boundary itself and our ways of recognition or ethnomethods of its use. This paper constructs some concepts of boundary transformation, multi-boundary, and distantiation.