The papers in this volume arose out of the workshop Membrane Transport and Renal Physiology, which was conducted as part of the IMA 1998-1999 program year, Mathematics in Biology. The workshop brought together physiologists, biophysicists, and applied mathematicians who share a common interest in solute and water transport in biological systems, especially in the integrated function of the kidney. Solute and water transport through cells involves fluxes across two cell membranes, usually via specialized proteins that are integral membrane components. By means of mathematical representations, transport fluxes can be related to transmembrane solute concentrations and electrochemical driving forces. At the next level of functional integration, these representations can serve as key components for models of renal transcellular transport. Ultimately, simulations can be developed for transport-dependent aspects of overall renal function. Workshop topics included solute fluxes through ion channels, cotransporters, and metabolically-driven ion pumps; transport across fiber-matrix and capillary membranes; coordinated transport by renal epithelia; the urine concetrating mechanism; and intra-renal hemodynamic control. This volume will be of interest to biological and mathematical scientists who would like a view of recent mathematical efforts to represent membrane transport and its role in renal function.