A study of the behavior of fluids in porous solids emphasizing interactions between the walls and fluids in the micro- and meso-pore ranges. The work will encompass statistical mechanical theory, computer simulation, and experimental verification. The principal goals are: (1) basis understanding of the role of slate conditions, pore material, and pore morphology on typical properties as phase transitions, layerigtransitions, adsorption, wetting, and diffusion, and (2) the application of the newly developed theory to suggest specificity of adsorbent species for particular applications. Initial studies will be with polycarbonate materials followed by experiments and theoretical studies on well characterized ceramic materials.