This report summarizes a preliminary analysis of possible mathematical models applicable to the problem of a steam-driven oil-shale retort. The modeling technique required must predict the transient, in-depth response of the pyrolizing oil-shale material, coupled to the behavior of the bulk steam-pyrolysis-gas system. The recommended procedure involves the adaptation of previously developed orthogonal collocation techniques for non-catalytic gas-solid retort operation. Recently announced computational procedures for the evaluation of the thermodynamic properties of the water-steam systems are discussed together with methods for the computation of transport properties of the water-steam system. It is to be noted that this report is preliminary only, but that the advantages inherent in the orthogonal collocation technique are sufficiently strong as to indicate that the method should be pursued to the implementation of an operational computational tool.