In 1622, Francis Bacon published his Historia naturalis et experimentalis. Many of the features of Bacon's natural and experimental histories were entirely new. This paper studies this literary form as a new epistemic genre. In particular, it analyzes its origin and evolution in Bacon's work, focusing on how its basic template and features were influenced by his specific epistemic requirements. It shows that Bacon devised these features in the process of developing a Historia mechanica, or a history of the mechanical (...) arts, drawing on the particular case of the technical recipe. Since antiquity, the recipe had been the dominant epistemic genre for recording and communicating technical knowledge. However, this paper suggests that the recipe format did not meet Francis Bacon's epistemic needs. In particular, the format was incompatible with the goal of keeping experimentation and its reporting open-ended and flexible. More generally, the acknowledgment of the provisional, historical character of knowledge was a tenet of what Bacon called an “initiative” method of knowledge transmission, or a method of “probation.” According to this approach, knowledge “ought to be delivered and intimated, if it were possible, in the same method wherein it was invented” and discovered. Only the display of its tentative features would encourage and stimulate others to improve and advance it. The format of the new genre of natural and experimental histories grew out of Bacon's dissatisfaction with the way in which recipes hid the imperfection of the process of knowledge production. (shrink)