... The Second Servicing Mission brought about major changes for the HST as the new Space Telescope Imaging Spectrograph (STIS) and Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) replace the Faint Object Spectrograph (FOS) and Goddard High Resolution Spectrograph (GHRS), and the Fine Guidance Sensors were upgraded. The Third HST Calibration Workshop will capture the impact of these changes and explore the new capabilities that they bring to the HST user community. ...