In previous chapters, I described personas and emphasized the importance of goals over tasks. Only after we know our user personas and their goals can we begin to examine tasks with confidence that they won't distort the design process. We call our tool for incorporating tasks scenarios. A scenario is a concise description of a persona using a software-based product to achieve a goal. In this chapter, I'll describe scenarios in more detail, along with a few other usefiil design tools. I'll follow with a case study of how some of diese tools, particularly scenarios, work in the real world.