Scientists, above all others, approach public policy believing it to be scientifically rational—as it has been portrayed by the Good Government Movement, the League of Women Voters, and Mark Twain. Today, the problem is that public policy does not appear rational to scientists. While there is great opportunity for scientific input, neither the policy process nor the most influential policy input is necessarily scientifically rational. To understand the relationship of science to policy, one has to look at how the public views science today, the style of policy, the style of science, and how the policy process may have been captured by “irrational” interests. Only then can a realistic marriage be made between science and policy.