Polycrystalline metals, porous rocks, colloidal suspensions, epitaxial
thin films, rubber, fibre reinforced composites, gels, foams, granular
aggregates, sea ice, shape-memory metals, magnetic materials, electro-
rheological fluids, and catalytic materials are all examples of
materials where an understanding of the mathematics on the different
length scales is a key to interpreting their physical behavior. In their
analysis of these media, scientists coming from a multitude of
professions have encountered similar mathematical problems, yet it is
rare for researchers in the various fields to meet. The chapters in this
volume have emerged from the 1995-1996 program at the Institute for
Mathematics and its Applications devoted to Mathematical Methods