For several decades, polymer science has sought to rationalize the mechanical and thermodynamic properties of polymer networks largely within the framework of statistical thermodynamics. Much of this effort has been directed toward the rubbery rather than the glassy state. It is generally assumed that networks possess an av- erage composition to which average properties may be assigned; from such a continuum view, a powerful analysis of such properties as modulus, swelling, birefringence and thermoelasticity has emerged. In the years following the rise of polymer characterization (the late...