Photographers from Niépce to today, from experiments in the darkroom to technical change and experimental research; the social environment, photography as a trade, its cultural, literary and aesthetic repercussions. In these dense pages the French scholar Jean-A. Keim, professor at the Institut d’Art et d’Archéologie de l’Université de Paris and at the École nationale de Photographie, takes on a range of questions that make photography a particularly lively chapter of the cultural experience of the last hundred and fifty years. An appendix written specially by Wladimiro Settimelli sheds light on the Italian side of the story.