Cover Illustration: The Visual Target Tuner (VTT) from the paper by Koratkar and Grosvenor (p. 57). The VTT is an interactive field-of-view visualization tool that allows the user to import images from several sources (including the NASA Extraterrestrial Database---NED, HST's Guide Star Catalogs, and the Digitized Sky Survey). Once imported the user can overlay an instrument's field-of-view positioning and orienting the target exposure visually. Overlays of multiple apertures can also be done visually. The VTT tool was developed as part of the Next Generation Space Telescope's (NGST) Scientist's Expert Assistant (SEA) program in a joint effort between Space Telescope Science Institute (ST ScI) and the Advanced Architectures and Automation Branch of Goddard Space Flight Center's (GSFC) Information Systems Center.