Jean Cavaillès writes his last work "On Logic and the Theory of Science" in prison. In it, he summarizes the essential lines of his lifelong engagement with the philosophy of mathematics and confronts them with four major theories of science: those of Kant, Bolzano, Carnap, and Husserl. Cavaillès' work is neither a historical study of the theory of science nor a description of its current state, but rather defines the conditions for the formation of conceptual structures that form the framework of science. The normativity of the rules that determine logic, the crucial role of proof, the autonomy of science, its necessary reference to the object, and its embedding in history are the guiding themes of this treatise, which undoubtedly ranks among the most important in the philosophy of science.