In this radical reinterpretation of Aristotle's Metaphysics, Walter Wehrle demonstrates that developmental theories of Aristotle are based on a faulty assumption: that the fifth chapter of Categories ("substance") is an early theory of metaphysics that Aristotle later abandoned. The ancient commentators unanimously held that the Categories was semantical and not metaphysical, and so there was no conflict between it and the Metaphysics proper. They were right, Wehrle argues: the modern assumption, to the contrary, is based on a medieval mistake and is perpetuated by the anti-metaphysical postures of contemporary philosophy. Furthermore, by using the logico-semantical distinction in Aristotle's works, Wehrle shows just how the principal "contradictions" in Metaphysics Books VII and VIII can be resolved. The result in an interpretation of Aristotle that challenges mainstream viewpoints, revealing a supreme philosopher in sharp contrast to the developmentalists' version.