Book excerpt: This latest two-part work provides a study of another significant arm of the Luftwaffe, the Aufklarungsflieger or reconnaissance units. Although such operations are sometimes erroneously perceived as being of secondary importance due to their lack of offensive function, the Luftwaffe was very advanced in understanding the benefits of reconnaissance. In fact no single arm of the Luftwaffe operated at such a wide number of aircraft types and many of the operations conducted by the Aufklarungsflieger units were of vital importance. This first volume will cover the aircraft and operations of the reconnaissance units from their origins in clandestine survey and photographic work over Poland and the United Kingdom in the late 1930s through to their first operational use during the Spanish Civil War. They were active in the skies across Europe, from Poland in the east to Britain in the west. They also played their part in the invasions of the Balkans and Russia. On the Russian and Mediterranean fronts, short-range reconnaissance usually involved low-level missions over enemy territory using the Fieseler Fi156 Storch and Hs126 biplanes, though Bf109s and Fw190s were also employed on such activities. Also included in this book will be an overview of the related "Wekusta" or weather reconnaissance units, responsible for the collection of meteorological data where, because of the proximity of the enemy, normal land-based observation was not available. These units were assigned directly to the Meteorological Service of the Luftwaffe High Command and were considered very valuable assets.