The 15 years from 1936 to 1950 are covered here in the fourth volume of the series. This was the period which saw the lifting of the world-wide recession of the early '30s and the introduction of the largest passenger vessel of all time, the famous Cunarder Queen Elizabeth, and the Wilhelm Gustloff, which was considered to be the first ship built for cruising in the modern sense. The Second World War had a devastating effect on the many ships then under construction and a number were never completed or were refitted for military purposes. A large section deals with the troop transports which were standard types of ships commissioned expressly by the Americans to serve during the latter part of the war years. With the ending of the war, several new passenger liners were laid down and were soon in service on the main shipping routes alongside the surviving pre-war veterans. Although not then appreciated, this was the beginning of an era in which the dominance of the passenger liner was fast becoming threatened by the aeroplane, whose speed and efficiency would soon make it a strong and important competitor. As with previous volumes, the historical and technical data of each vessel covered has been painstakingly researched and clearly presented. Arnold Kludas, who was formerly a technical engineer in a Hamburg shipping yard, is now working in the library of the Deutsche Schiffahrtsmuseum in Bremerhaven.