The book, Luftwaffe At War # 5: Messerschmitt Bf 109 in the West, (1937 - 1940) is part of an illustrated series of publications that presents every aspect of the German Air Force in World War II, on all fronts and in widely varying conditions.  Contemporary photographs from archives and private collections, many published for the first time, reveal how and where the many different types of German aircraft operated.  Detailed photograph captions written by experts in military aviation provide further clarity regarding the subject material.  "Luftwaffe At War # 5: Messerschmitt Bf 109 in the West, (1937 - 1940)" examines the early development of the Bf 109 single seat German fighter flown by the Luftwaffe from the Spanish Civil War through the Battle of Britain.  The Bf 109 was designed in 1934, by a team led primarily by Willy Messerschmitt, as a high-speed bomber interceptor.  Initial prototypes of the Bf 109 including the (V-4) flown by Hannes Trautloft were sent early on to Spain for flight evaluation purposes.  As a result of actively participating in aerial combat during the Spanish Civil War, many refinements were made especially in armament and engine performance in subsequent variants.  The initial A, B, C, and D series powered by the Junkers Jumo 210 series engine while better than the initial prototypes, were still relatively under-powered.  The definitive early Bf-109 variant was the E series or "Emil", which introduced a number of structural changes in order to incorporate the heavier but more powerful Daimler-Benz DB 601 engine, heavier armament and increased fuel capacity.  By the Battle of Britain, which began in July 1940, most German Luftwaffe squadrons in Western Europe had transitioned to the Bf 109 E.  "Luftwaffe At War # 5: Messerschmitt Bf 109 in the West (1937 - 1940)" contains four pages of introductory text that summarizes the action and operation of the initial V prototypes, as well as, the A through E variants flown from the Spanish Civil War up through the Battle of Britain.  In addition to these four pages of introductory text and authoritative picture captions, "Luftwaffe At War # 5: Messerschmitt Bf 109 in the West, (1937 - 1940)" includes the following features: 1) Approximately 93 black and white photographs and 2) About 10 rare wartime color photographs.  This book is 72 pages and is in excellent condition.  The author is Michael Payne.  Edition published in 1998.