The Admiralty List of Radio Signals series provides comprehensive information on all aspects of Maritime Radio Communications. The data is organized into six volumes, some divided into several parts for ease of handling. Each of the six volumes is presented in a user-friendly format with full color photographs and diagrams. The contents range from a complete listing of stations handling Maritime Public Correspondence to a full range of products and services essential for compliance with the GMDSS (Global Maritime Distress and Safety System). The volumes also feature radio stations broadcasting weather services and forecasts and a detailed explanation of the complexities of Global Satellite Position Fixing Systems. ALRS publications are presented in a user-friendly format and are updated through Section VI of the weekly editions of Admiralty Notices to Mariners. New editions are published annually containing all changes to information held.