According to a widespread stereotype, scientists occupy an ivory tower, isolated from other parts of society. To some extent this is true, and the resulting freedom to pursue curiosity-driven research has made possible extraordinary scientific advances. The spinoffs of 'pure' science, however, have also had powerful impacts on society, and the potential for future impacts is even greater. The public and many policymakers, as well as many researchers, have paid insufficient attention to the mechanisms for interchange between science and society that have developed since World War II. Ivory Bridges examines two such mechanisms; governmental science policy (often involving the participation of 'scientist administrators') and scientists’ voluntary public-interest associations. The examination of science policy is guided by the notion of 'Jeffersonian science' - defined as basic research on topics identified as being in the national interest. The book illustrates the concept with a historical case study of the Press-Carter Initiative of the late 1970s and proposes that a Jeffersonian approach would make a valuable addition to future science policy. The book also looks at the activities of citizen-scientists who have organized themselves to promote the welfare of society. It shows that their numerous and diverse organizations have made major contributions to the commonweal and that they have helped to prevent science from becoming either too subservient to government or too autonomous. An extensive appendix profiles a wide variety of these organizations.