A thesis statement usually appears in the introductory paragraph of a paper. It offers a concise summary of the main point or claim of the essay, research paper, etc. It is usually expressed in one sentence, and the statement may be reiterated elsewhere. It contains the topic and the controlling idea. There are two types of thesis statements: direct and indirect. The indirect thesis statement does not state the explicit reasons, while the direct thesis statement does. "I love New York for three reasons" is an indirect thesis statement because the statement promises three rationales to support the claim but does not include the reasons in the thesis statement itself. On the other hand, "I love New York because of the food, jazz clubs, and Broadway Shows," is a direct thesis statement because it specifies three reasons. The thesis statement is developed, supported, and explained in the course of the paper by means of examples and evidence. Thesis statements help organize and develop the body of the writing piece. They let readers know what the writer's statement is and what it is aiming to prove. A thesis statement does not necessarily forecast the organization of an essay, which can be more complex than its purpose. Source: Wikipedia (en)