“I begin with a definition, and illustrate my approach to partitioning the terrain of interaction design using five conceptual ‘lenses’. In so doing, I cover most of what I see as the theoretical roots of interaction design. I then turn to the role of theory in interaction design, and suggest that a good way to begin is to assemble a toolkit of concepts for interaction design that consists of appropriately sized theoretical constructs.” (Tom Erickson) – courtesy of elearningpost