The I-15, I-16 and I-153 fighters were the world's first mass-produced fighters. A total of 17,000 Polikarpov fighters had been manufactured by the time their series production was terminated in 1941. Aircraft of the first series successfully operated in Spain with the Republicans during the civil war (1936-39), in Chinese hands against the Japanese (1937-38), and then with the Soviet Red Air Force again against the Japanese in Mongolia during the Nomonhan Incident (1939). Russian-flown fighter also saw action against the Finns in 1939-40 during the Winter War. <br><br>By the time the Wehrmacht launched its surprise attack on the USSR on 22 June 1941, more than 20 Soviet pilots had made ace in Polikarpov fighters during these various conflicts. Still more aces were created in the first months of the German invasion, although losses suffered by the Soviet Air Force's five borderline military district units equipped with some 4000 I-15bis, I-153s, and I-16s were astronomical. Despite being thoroughly outclassed by the Bf 109E/F, the Polikarpov fighters constituted the backbone of Soviet fighter aviation for the first six month's of the war in the east. Many future aces started their combat careers in Polikarpov fighters, and newly-winged pilots continued to train on the I-15 UTI-4 two-seater until 1944. I-153s and I-16s actively participated in campaigns throughout 1942 and, in certain sectors of the frontline, into 1943. Amazingly, a handful of Polikarpov fighters remained in service through to 1945. <br><br>This is an important title that helps tell the story of fighter evolution 'between the wars', as the Polikarpov family of aircraft effectively bridged the gap between the biplane fighters of WW1 and the monoplane fighters of WW2. They also saw combat in all of the 'smaller' conflicts of the 1930s leading up to WW2. This book also features a significant chunk of Spanish Civil War material, as well as operations against the Japanese in the late 1930s - both areas are very popular with aviation historians and hobbyists alike.