"Do you believe in reality?" This question from a colleague surprised Bruno Latour. In this book, he provides his detailed answer. Through various case studies - a soil expedition in the Amazon rainforest, French atomic research just before the occupation, the discovery of lactic acid fermentation by Pasteur - Latour addresses the much-discussed question of whether the facts obtained in the laboratory are "constructed" or "real." However, this question is primarily intended to establish a polemical form of the scientific "object" and is part of the current "Science Wars," which he traces back to antiquity. Despite the instrumentalization of the sciences for the purpose of paternalism, Latour is not an opponent of science; rather, he advocates for research in its open experimentation.