The Dominican theologian Albert the Great (ca. 1200-1280) was one of the first to investigate into the system of the world on the basis of an acquaintance with the entire Aristotelian corpus, which he read under the influence of Islamic philosophers. The present study aims to understand the core of Albert's natural philosophy. Albert's emblematic phrase, “every work of nature is the work of intelligence” (omne opus naturae est opus intelligentiae), expresses the conviction that natural things are produced by the intellects that move the celestial bodies, just as houses are made by architects moving their instruments. Albert tried to fathom the secret of generation of natural things with his novel notion of “formative power” (virtus formativa), which flows from the celestial intellects into the sublunary elements. His conception of the natural world represents an alternative to the dominant medieval view on the relationship between the artificial and the natural.