In this paper I will discuss a system which uses vision to guide a mobile robot through corridors and freespace channels. The system runs in an unmodified office environment in the presence of both static and dynamic obstacles (e.g. people). The system is also among the simplest, most effective, and best tested systems for vision-based navigation to date. The performance of the system is dependent on an analysis of both the task and the environment in which it is performed. I will describe both of these and discuss how they simplify the computational problems facing the robot, as well as the performance of the resulting system. Finally, I will briefly discuss work in progress regarding place recognition and point-to-point navigation.