Noting that the National Council of Teachers of English Assembly for the Teaching of English Grammar is working towards formulating national goals for grammar instruction at all levels of schooling, this paper explores what teaching English grammar is all about. The paper contends that, acknowledge it or not, English teachers are engaged in a prescriptivist enterprise. It also finds that linguists, educated in a tradition which prides itself in being empirical and scientific, find it easy to look down on prescriptive rules and the unaccountable importance which the lay public attaches to them. The paper discusses the historical motivation for standardization, which began with the advent of printing, and considers the ideas of the American structural linguists in the 20th century. It also looks at some recent arguments which appear to deny much value for a Standard. The paper describes the "iron fist" type of prescriptivism and the "velvet glove" type of prescriptivism. It concludes by illustrating the insecurities experienced by an ordinary, educated speaker of English in the face of the realities of sociolinguistic variation and proposes that the goal of teachers of English grammar should be that all students consciously know the most important principles of Standard English. (Contains 14 references.) (NKA)