In defining an audience, writers make guesses about the mutual knowledge shared between writer and readers, and thus send cues to readers that exclude them from the audience for a specific discourse. Often writers assume that readers possess more knowledge than they actually do, and so make it impossible for readers to function within the world of the discourse. This phenomenon is most obvious in government and legal documents, and can border on the criminal, because needy people are denied full access to government services and to the courts because of a lack of understanding of the discourse. Yet it is not only disadvantaged or poorly-educated readers who are excluded from writings. Text inaccessibility seems to be part of a wider trend, affecting all sectors of our society, including the scholarly and professional communities. As a consequence of incomprehensible texts, more and more decision-making is relegated to experts. Teachers of writing must make students aware that there are many potential audiences for almost any piece of writing, and the way in which they exploit mutual knowledge will determine which readers will be brought into their texts and which readers will be excluded. One suggested way to do this is to have students write the "same essay" for more than one audience. (ARH)