The Foundations of Science gathers Henri Poincaré's three major philosophical works-Science and Hypothesis, The Value of Science, and Science and Method-into a lucid inquiry into how scientific knowledge is formed, justified, and revised. Moving between mathematics, physics, astronomy, and logic, Poincaré examines convention, intuition, experiment, and creative discovery with a style at once elegant, aphoristic, and rigorously analytical. The book stands at a crucial moment in modern thought, anticipating debates over relativity, formalism, and the philosophy of science. Poincaré, one of the last universal mathematicians, was not merely theorizing science from outside it: he helped shape celestial mechanics, topology, number theory, and mathematical physics. His reflections arise from a working scientist's intimacy with abstraction and empirical constraint. His famous emphasis on hypothesis and convention reflects both his mathematical practice and his awareness that scientific "truth" depends upon structures chosen for their coherence, economy, and fruitfulness. This volume is recommended to readers seeking a profound yet accessible account of scientific reasoning before the full upheavals of twentieth-century physics. Philosophers, historians of science, mathematicians, and intellectually curious general readers will find in Poincaré a rare guide: skeptical without cynicism, rational without dogmatism, and deeply attentive to the imagination that makes science possible.