The history of the evaluation of non-English written materials through the use of various mathematical formulae is reviewed. This process began in 1939 with Tharp's work in French, and has continued until the present. Formulas have been developed for Spanish, Russian, German, Hebrew, Chinese, and Vietnamese. In Europe, modifications of the Flesch Reading Ease Formula were adapted to French, Spanish, German, and Dutch, while different methods were used to evaluate many other languages. More recently, in Denmark, Austria, and other European countries, techniques have been developed that involve the examination of factors other than linguistic ones (i.e., the visual presentation of the material and the contents of the text. In the United States and Canada recent research has concentrated on the evaluation of the readability of minority-language texts such as French in Canada, and Spanish and Vietnamese in the United States. (JL)