In this paper, I suggest that our methods for how to train are based historically on what we understand learning to be. I briefly trace the history of instructional design models, which embody both first-generation objectivist and second-generation cognitive constructivist views of learning. I then suggest we are on the cusp of a third-generation instructional model, one that places greater emphasis on the learner forming understanding largely through a process of social negotiation, either in training or on the job. I argue that Web-based instruction offers a technology ideally suited to the social constructivist approach at the core of this third-generation model. I discuss the importance of interaction in learning and suggest why Web-based networked learning may result in more, not less, interaction during training. Finally, I discuss other applications of third-generation learning such as peer mentoring and professional forums.