A PRIMARY GOAL of most introductory business and technical communication courses is to introduce students to the idea that the professional communication most of them will engage in is different from the writing they do for academic purposes. This overall idea covers several principles concerning professional writing. First, in an academic essay, a student may tell all he or she knows about a topic to an expert reader (the instructor); in professional writing situations, however, writers are most likely sharing only a small part of the information they know with nonexpert readers. Second, when writing in professional situations, writers must actively envision audiences different from themselves, audiences that will have different concerns and purposes than the writers do. Finally, the audience, purpose, and medium of a professional communication situation drive the choices a writer will make. If students are to understand these principles, discussing them in class is insufficient; students must also practice them.