Born in 1765 in Chalon-sur-Saône, Nicéphore Niepce had a passion for inventions. In 1816, at the age of 51, he began research into how to fix images projected into a camera obscura. After several years, he invented heliography, the world's first photographic process. He then went into partnership with Daguerre, the future inventor of the daguerreotype. This is the author's account of his research, based on a genuine historical and scientific investigation. Drawing on the inventor's correspondence, he has, for the first time, experimentally reconstructed the processes described by Niepce and Daguerre, which have never been reproduced since their work. Their rediscovery reveals hitherto unknown processes, such as the physautotype. It shows what the world's first photographs looked like, and sheds light on the hitherto little-known approach of the inventor of photography.