Building on user familiarity with one-dimensional scroll bars, many designers simply use two one-dimensional scroll bars when the application requires independent control over the horizontal and vertical directions, as in panning a map. This is effective if users frequently move in a single direction by small increments of less than one screen, but in many cases this solution is inadequate. The requirements of more complex applications suggests that more careful analysis, design, and evaluation might lead to significant improvements. Indeed, our exploration of existing 2D browsers has led us to identify many features and a wide variety of tasks performed with the browsers. Here we introduce an informal specification technique to describe 2D browsers and a task taxonomy, suggest design features and guidelines, and assess existing strategies.