The Philosophiae naturalis adversus Aristotelem libri XII of 1621 is the first textbook in natural philosophy to combine anti-Aristotelian arguments with explicit corpuscularianism. While its uniqueness resides in the pioneering role it played in the history of the neo-atomist movement, its fateful attraction lies in the almost complete anonymity of its author. No other novator in the history of early modern thought has been as elusive as the man known as Basso, Basson, Bassus, or Bassone. This essay consists of two parts. The first part places the Philosophia naturalis within its time and summarizes its main theories, emphasizing the larger themes and the tensions found between its conflicting accounts of causality. Special attention is drawn to Basson's dual approach to atomism, namely physical and theological, which are not complementary, but contradictory. The fortuna of Basson from his own age down to his current status in the history of science is examined next. In combination with his methodological heterogeneity, Basson's anonymity are found to have led to disparate assessments of his aims. In the current literature, Basson figures as a Neoplatonist, a pre-Cartesian occasionalist, the earliest molecular chemist, a Renaissance studioso, a Stoic philosopher and a Calvinist zealot. The second part of this essay tries to improve this situation. Recently discovered documents show that Basson, after a Jesuit education in the 1590's and subsequent medical studies, became a Protestant. He spent the years 1611 to 1625, to which our documents relate, at the smallest of French Huguenot academies in the mountain town of Die (Dauphiné) where he taught at the local Collège. An analysis of Die's difficult historical circumstances, of its little academy and its official natural philosophy, and finally of Basson's own uneasy sojourn in the Dauphiné elucidates several aspects of the Philosophia, notably the theological motifs in Basson's atomism, the outdatedness of his astronomical and optical expertise, the argumentative reliance on late scholasticism, its "eloquent" style, and the timing of the publication. Yet it is undeniable that the context cannot account for the Philosophia itself, whose relation to Basson's circumstances remains perplexing. The author's conflict with the Genevan censors demonstrates that an explanation of his views in terms of Calvinist theology alone cannot explain the contents of his book. Our findings point towards the variegated nature of the forces behind the neo-atomism of the early modern period, and they force us to reconsider the coherence of the movement itself and the motifs of its proponents.