This document defines the thesis statement and discusses how to write an effective one. A thesis statement outlines the main argument and supporting ideas in one sentence. It has three parts: a claim, a link using "because," and at least three reasons. The document provides examples of different thesis templates for types of essays like definition, evaluation, and proposal. It also lists criteria for evaluating whether a thesis encourages reading further and takes a clear stand that can be supported. Additional resources for writing thesis statements are recommended.