This research project in materials physics employs x-ray and neutron scattering methods to address a range of problems in the structure of matter. The interest on the one hand is with atomic structure relationships, and on the other with those details that lead to important physical properties. Topics include interfacial disorder in multilayers, replacive disorder and order-disorder transitions in metals, semiconductors and superconductors; orientational disorder in molecular solids; displacive disorder in structural transitions, and the effects of surface on disorder and phase transitions. The project includes computer modeling and simulation, and collaborations with theorists. Materials under study include quasicrystals, superconductors, fullerenes, vanadium hydrides, metals with martensitic transitions, and multilayers of various metals. The research provides excellent training for graduate students and post-doctoral associates in x-ray, neutron, synchrotron x-ray and small angle x-ray scattering methods. Because of the breadth of materials under study, students receive an excellent background in materials physics and are prepared for a range of scientific or technical careers. %%% This research project in materials physics uses x-rays and neutrons to probe atomic arrangements in many different types of materials. The task is first to determine how the atoms are arrange in the solids and then to determine how the physical properties of the materials depend on the atomic arrangements. The materials under study include high-Tc superconductors, metals, fullerenes (bucky-balls), semiconductors, and multilayers of metals and semiconductors. The experiments depend strongly on computer modeling and simulation, and interaction with theorists. The research provides excellent training for graduate students and post-doctoral associates in x-ray, neutron, synchrotron x-ray and small angle x-ray scattering methods. Because of the breadth of materials under study, students receive an excellent background in materials physics and are prepared for a range of scientific or technical careers.