Other
Research Assistant: For Students: Purpose Statement
This site gives advice on how to write an effective purpose (thesis) statement. The summary is given as answers to four questions: what? why? when? how?.
University of Wisconsin
Univ. Of Wisconsin Madison: Writing Center: Thesis and Purpose Statements
Explains the thesis statement and distinguishes it from the purpose statement. Gives an example of a paragraph containing both. Be sure try the link at the bottom of the page, "Developing a Thesis Statement." This page goes into further...