The overhead projector (OHP) is described as one of the simplest and most versatile resources available to the language teacher, yet one that is frequently undervalued and underutilized. It can be used to support classroom practice in many ways: enhancing and expanding group and pair work; stimulating the use of target language by pupils; ensuring progression; assisting the teacher in use of the target language; clarifying difficult concepts; and revising and reinforcing vocabulary and structures. Seven chapters are devoted to methodology, showing how the OHP can be used effectively for language input, language games, real communication, model exercises, support for the target language, grammar, posters, songs, story telling, and in organizing group work. Three additional chapters deal with the practicalities of preparation of good quality transparencies and of the most efficient use of OHP in the classroom. Instructions for maintaining the equipment are appended. (LB)