Leonardo's complex and profound personality expressed itself in nearly all fields of scientific and artistic endeavor: architecture, painting, botany, geology, physics, geography, engineering, and anatomy. In each of these disciplines, he achieved innovative results. His keen curiosity for empirical investigations made him a pioneer of the experimental method that was to characterize science in later centuries. By dissecting corpses, he was able to produce anatomical drawings in which his direct vision of the body challenged the bookish teaching of traditional doctrine.