When German forces initiated the assault on the Soviet Union on June 22, 1941 the Luftwaffe enjoyed almost total supremacy. The fighter element of the Soviet Air Force was immersed in a major re-equipment programme resulting from belated appreciation of the fact that its aircraft had fallen woefully behind world standard. This first part of a two-part Fact File - devoted to all types of indigenous fighters operated by or developed to experimental status for the Soviet Air Forces - is primarily concerned with the products of the design bureaux led by Lavochkin and the partnership of Mikoyan and Gurevich, whose fighters, when first opposed by the Luftwaffe, enjoyed indifferent success. Whereas the Mikoyan-Gurevich team largely concentrated its wartime efforts on creating specialised high-altitude fighters which were to receive low development priority owing to more pressing needs, Lavochkin was to overcome early setbacks and achieve outstanding success by the continuous refinement of one basic design; a process epitimized by the La-7 which played a major role in the closing stages of the conflict.