In this thesis I have attempted to show the part played by Coastal Command in World War II. I have given emphasis to the two main roles of Coastal Command, namely its work in anti-submarine warfare in the Battle of the Atlantic, and the Command's anti-shipping operations against both warships and merchant vessels. Coastal's other roles, including meteorological flights, Air-Sea Rescue, minelaying, and photo-reconnaissance have also been considered. By the nature of such work, Coastal Command did not gain the recognition it deserved, and was overshadowed by Fighter and Bomber Commands which generally were given priority in respect of aircraft and equipment. As the prime needs of an Air Force in war were aircraft and armament I devoted two chapters to those subjects, taking the view that some understanding of such technical aspects are essential for a proper appreciation of Coastal Command's work. The thesis is based on the following primary sources; operational records of squadrons, the Command's records, and some Cabinet files. Additionally, I have corresponded with many Coastal Command veterans in addition to interviewing others. The retrospective views of some of those former aircrew have been included. My 'research' really began on 3rd April 1939 when I joined the RAP for training as aircrew, but my wartime operational flying with Coastal Command began in February 1942 and ended May 1945. I therefore consider that this thesis which I can claim was written from the 'inside', presents the subject by one who was actively involved. Themes have been, that although Coastal Command was the 'Cinderella' in respect of aircraft, equipment and publicity, it surmounted those limitations and made a considerable contribution to the Allies' war effort.