The measurement of the evolution of illiteracy is the focus of this study. An elementary method for estimating the short-term evolution of the number of illiterates forms the subject of the first part of this analysis. This method is based on the demographic growth rate, the product of the school system and past trends. The second part is devoted to the examination of the evolution of the number of illiterates and of the rate of literacy in an attempt to arrive at coefficients which may facilitate the adoption of a literacy policy based more on rational than on empirical considerations. It is divided into two chapters, the first one relating to the evolution process of illiteracy. This evolution is influenced by the growth rate of the number of newly literate, the initial literacy rate, the rate of demographic growth, these various factors being taken together. The second chapter shows how to measure changes in the literacy rate and in the number of illiterates. Changes in the literacy rate depend on: the initial literacy rate; and the difference between the rate of increase of those made literate and the demographic growth rate. The number of illiterates diminishes when the rate of increase of those made literate is higher than the result of the demographic growth rate divided by the literacy rate of the previous year. (Author/DB)