The document discusses writing as a tool for expressing knowledge. It provides guidance on analyzing the audience for a written work, including considering the audience's attributes, attitudes, knowledge, and expectations. The document also discusses different purposes for writing, such as to explain, persuade, or entertain. It provides an example of analyzing the audience and purpose of a text about Darwin's theory of evolution and genetics. The document encourages identifying multiple purposes and audiences that could be targeted through different papers on a single research topic.