On the same day that Mike Huckabee won the Republican presidential caucus in Iowa ? having revealed during a candidates' debate that he does not believe in the theory of evolution ? the US National Academy of Sciences released its latest version of a book to explain to the American public why evolution works.

It is the third time that the academy has weighed in with such educational material. ?We're trying to give the public coherent explanations and concrete examples of the impact of evolution,? says academy president Ralph Cicerone. The book, Science, Evolution, and Creationism, is available at http://www.nap.edu/sec . It includes descriptions of fossils such as the Canadian Tiktaalik, a creature that had features somewhere between those of fish and four-legged walking animals.

The Institute of Medicine also weighed in as a co-sponsor of the book, citing the importance of evolution for understanding infectious and emerging diseases today.