In November l982, the American Council on the Teaching of Foreign Languages (ACTFL) published the ACTFL Provisional Proficiency Guidelines, a series of descriptions of proficiency levels for speaking, listening, reading, writing, and culture in a foreign language. The history, origins, objectives, and implications for language teaching of those guidelines are examined to give a sense of the current interest in proficiency as the organizing principle of foreign language study. The antecedents of the proficiency guidelines are traced from ancient history through the twentieth century, when intensive language instruction became of interest. The effects of the intensive language teaching efforts are chronicled in government and academic instruction after World War II. The beginning and expansion of post-war oral proficiency testing outside the government through Foreign Service Institute testing kits are described, and the immediate antecedents of the ACTFL Guidelines are outlined. Finally the place of the ACTFL Guidelines in the proficiency-oriented program, and future directions, are briefly discussed. (MSE)