This report compares three fire spread models, recently developed for the Office of Civil Defense, for utility, accuracy, and efficiency when applied to civil defense fire information requirements. The fire spread modeling was essentially limited to the radiation fire spread mechanism. All three models provided procedures for calculating fire spread under a limited range of conditions, but all suffered to some degree from inadequate modeling of urban configurations and the fire parameters associated with urban structures that significantly affect fire spread mechanisms. It is recommended that a "reference" fire spread model be structured for evolutionary development. Although none of the models considered could provide a sufficiently broad base upon which a "reference" model could be built, parts and concepts from all three models could be incorporated. The "reference" model should be structured in terms of fire spread mechanisms by developing fire spread submodels that are then analyzed at the most basic level and subsequently, systematically broadened in scope. Models for specific purposes and having predictable characteristics can be derived from the "reference" model by making appropriate simplifying assumptions. Fire spread modeling approaches and concepts are also suggested.