The examples discussed in this paper represent a sampling of how the inherently nondestructive techniques of thermal neutron scattering are being adapted to practical problems in the understanding of materials properties. The high penetration and selective scattering properties of neutrons provide a powerful, and often unique, capability to study, for example, changes in the microstructure of bulk specimens maintained in extreme environments. The principal drawback of the neutron methods is, of course, that the required fluxes are at present available only from research reactors. Thus the methods are limited to the study of prototypes rather than production-line or in-field examination.