This book opened by advocating the common metaphor of tool use for thinking about command-based systems, where command lines are the tools people employ to manipulate the materials in their computer environment. The four preceding chapters pursued the notion that recently used lines, like tools, should be available for reuse. But reuse is not the only strategy for supporting user activities. It is evident that people impose some organization on their computer tools and materials, just as craftsmen do with their physical counterparts. Real workshops support these organizations through toolboxes for arranging and locating tools, workbenches for performing specific tasks, shelving and drawers for keeping relevant tools and materials readily available, and so on. Computing environments, on the other hand, do little to promote personal organization. A command-based interface is comparable to an unhelpful clerk who waits for you to name the tool you want, retrieves the tool (if available) from a separate room, and demands that you return it immediately after use. At the other extreme, arranging facilities into fixed taxonomic menus is reminiscent of a totalitarian chaining of tools to a single location.