The document provides information on how to write an effective thesis statement for an essay. It states that a thesis statement should be one sentence, but sometimes may require more than one sentence. It presents the main idea or argument of the essay and lets the reader know what to expect. The entire essay is based on proving the thesis statement correct. There are different types of thesis statements, such as open versus closed theses. A closed thesis includes the main body points that will be discussed in the essay. When writing a thesis statement, it is important to include a subject and opinion, and possibly a counterargument, to make it more complex.