Volume 18 corrects some old data entries in previous volumes, provides additional ship movement data and adds new information in the General sections to help clarify the context of the war–especially important here in these early months. The bulk of the new material concerns Imperial Japanese Navy ship movements as Japan consolidates her hold on Chinese ports and eliminates French Indochina as a source of supplies for the Nationalist Chinese. Japan begins an extensive initial buildup of naval vessels as she prepares for the fateful move to attack the US Navy and extend the Japanese Empire into Malaya, Borneo and the Dutch East Indies. In addition, we add new data on the Royal Indian Navy and the Royal New Zealand Navy, and we expand the data on the following events: The Battle of the River Plate, Fleet Air Arm actions off Norway, and naval events off Ethiopia and Somalia.