The Official Chronology of the U.S. Navy in World War II, published in 1999 and updated here in a new format and with a complete index of all ships mentioned in the text (no index was included in the 1999 edition), is the authoritative resource on the war at sea between 1939 and 1945. Author Robert Cressman provides a nearly day-by-day account of navy-related engagements, operations, and activities in all theaters of the war. Appendices list the names and dates of service of the Navy's complex command structure and explain the abbreviations used in the text. A complete index of allied, axis, and neutral vessels is provided, as well as a secondary condensed index of important allied ships.