Published 150 years ago, Charles Darwin's On the Origin of Species - the text that introduced the world to natural selection - is among a handful of books that have changed the world. But the route to that status has been surprisingly circuitous and uncertain. Darwin's profoundly revolutionary message has often been misunderstood, as have his own views on evolution, the intellectual background that led to them, and the turbulent history of their reception.

Now, in 24 absorbing lectures by an award-winning teacher, you learn the remarkable story of Darwin's ideas, how scientists and religious leaders reacted to them, and the sea change in human thought that resulted.

You'll learn how Darwin arrived at his theory of natural selection-the idea that those members of a species best equipped to survive will tend to outlast others, thus changing the species over time-very slowly and cautiously. For he was all too aware of the intellectual dynamite inherent in its implication of no divine intervention being necessary for a rich diversity of life forms on earth.

And you'll see how Darwin worked out the details of his theory not only by building on both his own observations and the insights of others, but also through amazing leaps in the face of apparently contrary evidence. You'll also see how the firestorm of religious criticism Darwin's theory faced has scarcely subsided to this day, with Professor Gregory bringing this controversy up to date by carefully examining the claims of intelligent design, the latest and most sophisticated attempt to challenge Darwin on religious grounds.