The goal of this issue of the MRS BULLETIN, with its focus on the physics of complex materials, is to point out some of the fascinating features, both fundamental and applied, of complex materials: liquid crystals and polymers. Over the past 20 years, we have witnessed impressive advances in the understanding of liquid crystals and polymers on all fronts—physics, chemistry, materials research, and applications.

Physicists are interested in the fundamentals of a phenomenon. Our assumption is that once we understand how the pieces of a System work, the understanding of how the whole System works immediately follows. However, those of us who have been involved in materials physics research quickly learn that complexity generates rules of its own on scales much larger than the microscopic scale of the molecules involved. Some-times these rules are beautifully simple and elegantly described, but most often they are not. The following articles high-light some important current research in the domain of complex materials, particularly for liquid crystals and polymers.

Contributing to this special issue are: Pierre-Gilles de Gennes; J. William Doane; Wolfgang Meier and Heino Finkelmann; Paul Keyes; Patrick Oswald, John Bechhoefer and Francisco Melo; and Walter Zimmerman. They give us their current thinking on polymers in shear, novel electro-mechanical effects observed in polymeric liquid crystals, and how liquid crystals in a solid polymer matrix make useful high-speed color displays.