The history, development, and content of the notional-functional "threshold-level" (T-level) syllabus and the application of its principles in the preparation of new second language instructional materials are outlined. The context for development of the syllabus by the Council of Europe was based on the need for a uniform, sequenced program of second language learning applicable to all European languages and in all European countries. Examples are given for adult instruction in English as a second language. Despite the fact that very few courses or texts based entirely on T-level syllabus principles have been designed, the work focusing on the semantic and social aspects of language has been worthwhile. Forty-six references are included. (MSE)