Semiconducting and metallic polymers: The fourth generation of polymeric materials

When asked to explain the importance of the discovery of conducting polymer s, I offer two basic answers: They did not (could not?) exist, and they off er a unique combination of properties not available from any other known ma terials. The first expresses an intellectual challenge; the second expresse s a promise for utility in a wide variety of applications. This Nobel Lectu re, presented in Stockholm on December 8, 2000, summarizes the discovery an d development of the field of semiconducting and metallic polymers.