Much is known about the Leica and its history and numerous publications have appeared over the years. It thus seems incredible that a camera handmade by its inventor Oskar Barnack in the early 1920s - the "first Leica" - could re-emerge after having fallen into oblivion. This test camera finally evolved into the Leica over the course of various enhancements, leading to a very impressive success story. Encounters with landmark events in the history of technology - the first microscope, the first calculating machine, the first explosion-proof miner's lamp, the first steam engine, the first train, the first telegraph, the first car, the first light bulb, the first radio, to name just a few randomly selected inventions - are always ambivalent. The fascination of the "first step" competes with misgivings regarding the "teething troubles" of the prototypes, which are only cured by subsequent improvements. When Dr. Günter Kisselbach found a relatively unknown Leica prototype, "Barnack's handmade prototype" in his father's Leica collection, the history of development of the 35mm camera from Wetzlar had long been written. Fortunately, the wealth of established knowledge did not deter the photography enthusiast from finding out himself that substantial "blind spots" still existed in the source area of the Leica history. His fascinating report of his experience with the camera proves conclusively what this early personal model belonging to its inventor Oskar Barnack was capable of achieving. However, this only became apparent when the handmade prototype was subjected to practical testing and had to demonstrate the requirements it was equipped to meet and the points where it reached its limits, which it was only able to overcome in the course of further development. This book provides answers to intriguing questions: - what happened to Oskar Barnack's "forgotten test camera"? - what technical secrets does this camera hold? - can it still be used to take photos? - what is its position in the Leica lineage?