In order to comprehend the philosophy behind modern writing instruction in the English-speaking world, it is essential to have an understanding of the long and complex development of the art of rhetoric in the West. The history of rhetoric in the western tradition covers some 2,500 years and during this time the discipline has accumulated a variety of principles and shifts in emphasis that reflect the changing needs of those who practice it. Modern rhetoric finds its roots in the past but also responds to contemporary concerns, as it is a field of study which constantly changes to suit the purposes of language use by human beings.The term rhetoric has thus taken on a wide range of meanings, and every historical period has characterized the rhetorical tradition differently, sometimes focusing on oral discourse, sometimes on written texts, sometimes defining it narrowly as having to do solely with style, or delivery, or invention, sometimes viewing it as including a wider range of the arts and forms of communication in general. In this way, rhetoric has accumulated a multiplicity of connotations over the centuries, making the formulation of a comprehensive definition difficult, for it denotes both a practice and a body of knowledge describing that practice. Yet an understanding of the historical matrix from which the art of rhetoric in the western tradition arose is fundamental today if we are to comprehend the canons and strictures that govern our use of modern English prose.