This document summarizes research on coupled heat and water transport in bare soils. It outlines the theory of Philip and de Vries, describes field data collected, and calibration of the Hydrus-1D model. Both liquid water and water vapor fluxes are examined. Implementation of water vapor flow in the SWAP model is discussed. Comparisons of coupled and liquid-only models show little difference at daily timescales. A proposed laboratory experiment is described to further study these processes.