The theory of evolution is often disparaged by its opponents as being "just a theory"–i.e., a speculative hypothesis with little basis in hard, scientific facts. But this claim carries with it the implied accusation that Charles Darwin was "just a theorist"–i.e., that he was merely an armchair scientist and that his life's work was nothing more than an exercise in arbitrary speculation. A look at Darwin's pioneering discoveries, however, reveals the grave injustice of this accusation. Darwin was not "just a theorist" and evolution is not "just a theory." In this talk, Dr. Lockitch explores Darwin's life and work, focusing on the steps by which he came to discover and prove the theory of evolution by natural selection.