The mathematical fire model can be effectively used to predict fire behavior in wildland fuels. In 131 experimental fires, nearly half of the observations were within 25 percent of over- or underprediction, and 95 percent of the differences between predicted and observed values were less than 10 ft/min. When the model is used as a part of a fire management system, its success depends on accurate deterimination of fuel and environmental conditions and correct interpretation of predicted fire behavior. An example is the use of the model by well-trained fire behavior officers in predicting fire perimeter location when the fire is burning in surface fuels, and in predicting the potential of extreme fire behavior. When the basic assumptions of the model are met, predictions are successful over a wide range of conditions. Through continued testing and application, we will gain a better understanding of the situations to which it can be applied. © by the Society of American Foresters. Abstract reproduced by permission.