With the ever increasing amount of digital information, users desire more screen real estate to process daily desktop computing work, and might well benefit from using a large high-resolution display for information management. Unfortunately, we know very little about users' behaviors when using such a display for daily computing, and current user interfaces are mainly designed for normal-sized desktop monitors, which might not well suit a large display. In this article, we first present a longitudinal study that investigates how users manage overflowing digital information on a wall-sized display in a personal desktop computing context by comparing it with single and dual desktop monitors. Results showed users' unanimous preferences of working on a large display and revealed large-display users' unique activity patterns of managing windows. Guided by the study results, we designed a set of interaction techniques that provide greater flexibility in managing multiple windows. They include facile methods for selecting, moving, and resizing multiple windows using an active window boundary called Fringe, rearranging selected windows using multi- and single-window marking menus, packing/unpacking the selected windows using easily activated icons, and freely adjusting the order of overlapping windows with a Jab-to-Lift operation. We coherently integrated these techniques with traditional operations in a large-display window management prototype called WallTop. Two rounds of usability testing showed that users can quickly and easily learn the new interaction techniques and apply them to realistic window management tasks on a large display with increased efficiency.