Chapter 1: Introduction 1.1 About this Document 1.2 Resources, Documentation and Tools 1.2.1 Cycle 12 Announcement Web Page 1.2.2 Cycle 12 Call for Proposals 1.2.3 Instrument Handbooks 1.2.4 The Astronomer's Proposal Tool (APT) 1.2.5 Exposure Time Calculators (ETCs) 1.2.6 The Visual Target Tuner (VTT) 1.2.7 HST Data Archive 1.2.8 Data Reduction and Calibration 1.3 STScI Help Desk 1.4 Organization of this Document