Robert Root-Bernstein is a post-doctoral fellow in Theories in Biology at The Salk Institute for Biological Studies, San Diego 92138. He received his A.B. in biochemistry and his Ph.D. in history of science from Princeton University, where he also taught biology. He has been the recipient of several prizes and fellowships for scholarship, including a MacArthur Prize Fellowship (1981-86). Dr. Root-Bernstein is the author or co-author of many articles, including, recently, a chapter in Evolution and Creationism (Ashley Montagu, ed., The University Press, Oxford, England, 1982). Donald McEachron is a doctoral student at the University of California, San Diego and a biology laboratory technician with the Veterans Administration Medical Center, San Diego 92117. He received his B.A. from the University of California, Berkeley, where he received honors in behavior genetics and general scholarship. Mr. McEachron has also co-' authored a number of articles and papers, and holds memberships in several professional organizations such as the Animal Behavior Society, AAAS, AIBS, and the Society for the Study of Evolution. In recent years, a controversy has developed in the United States over the teaching of evolutionism and creationism in the public schools. The controversy, while nominally a scientific one, also has philosophical, historical, religious, and legal implications as well. Since some twenty state legislatures or courts are presently considering or have considered legislation and lawsuits concerning the controversy, we believe that it is in the best interest of the voting public to be informed of the issues. We believe that there are four basic issues: 1) What is a scientific theory? 2) What is. a religious belief? 3) Who has the right to decide these issues? 4) How does one's answers to the previous three questions affect one's view on whether evolutionism and creationism are scientific and should be taught in public schools. Very briefly, a controversy has arisen between evolutionists and creationists because they disagree on all four basic issues. Evolutionists generally believe: 1) that evolutionism is a valid scientific theory, whereas creationism is not; 2) that evolutionism is not a religious belief, whereas creationism is; and 3) that the validity of a religious belief should be decided by religious believers. In consequence, evolutionists conclude 4) that since evolutionism is a valid scientific theory, it should be taught in the public schools; whereas, since creationism is not a scientific theory, it should not be taught as science in the public schools.