This book is a must-read for anyone interested in the modern scientific controversy over origins. Michael Behe, Professor of Biochemistry at Lehigh University, claims that over the past decades, biochemical discoveries at the nano-scale have thrown Darwin's theory of evolution into an unresolved crisis. It simply cannot account for the molecular complexity of life. Recent advances in science have in fact discovered evidence of intelligent design, though sociological and philosophical factors have caused this discovery to be repressed.

Behe takes up a challenge set up by Charles Darwin in his book The Origin of Species:

If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find no such case.

Such cases are now known to exist, claims Behe, in the biochemical machines, pathways and systems of every living cell. To Darwin, the cell was a "black box"; he had no idea of what was going on inside, and assumed it must be very simple. Now that this black box has been opened, we must reassess Darwin's theories, testing them against the new data.

Behe describes several structures found within cells, which could not "have been formed by numerous, successive, slight modifications" describing them as "irreducibly complex." His examples include: the bactrial flagellum, a minature motor made up of over 40 parts, all necessary for function; the blood clotting mechanism of humans, a cascade of interacting chemicals; and the synthesis pathway for AMP, basic to life in all cells.

Behe guides the reader through the complexities of these structures with clear descriptions, vivid illustrations and contagious enthusiasm for scientific research. Having outlined the problem they pose to Darwinian evolution, he surveys the scientific literature for solutions. Scouring the libraries of the world, including publications such as Journal for Molecular Evolution and Proceedings of the National Academy of Sciences he finds nothing which can tell him how these irreducibly complex structures evolved. Eventually he concludes that no such explanation exists.

How then did these structures come to be? The answer, says Behe, is obvious:

There is an elephant in the roomful of scientists who are trying to explain the development of life. The elephant is labeled 'intelligent design.' To a person who does not feel obliged to restrict his search to unintelligent causes, the straightforward conclusion is that many biochemical systems were designed. They were designed not by the laws of nature, not by chance and necessity; rather they were planned. The designer knew what the systems would look like when they were completed, then took steps to bring the systems about. Life on earth at its most fundamental level, in its most critical components, is the product of intelligent activity. (p. 193)

The remaining chapters are an explanation of the scientific nature of the inference to design, the history of the idea, and the reasons why many scientists are relunctant to use design as an explanation.

Many Darwinian scientists have reviewed this book since its publication, and tried to refute its arguments. Behe has responded to some of these in a chapter Irreducible complexity: obstacle to Darwinian evolution in Debating Design: From Darwin to DNA , W. A. Dembski and M. Ruse Eds (Cambridge University Press, 2004).

This book is superbly written and is an excellent an essential introduction to the scientific theory of intelligent design.