We learn to write by writing and also by reading the writing of others. To help students identify purpose and audience and appreciate how these factors shape writing, collect writing samples on the same topic from different sources. For a topic like diamonds, for example, you might find an encyclopedia article, an editorial on the political and/or environmental implications of diamond mining, a financial report on the diamond industry, and a piece of ad copy from the De Beers company. Depending on the length of your writing samples and the time you have in class, have students read the samples in class or study them as a take-home assignment. Ask students to identify the purpose and audience for each sample. While each sample focuses on diamonds, ask students to comment on how each writer established a narrower focus based on purpose and audience. In addition to enhancing students' understanding of rhetorical context, this activity will promote a definition of writing as an activity that extends beyond the classroom and will help them see connections between academic and other kinds of writing.