The study-in-progress examines the treatment of the U.S. Constitution in U.S. history textbooks at the fifth, eighth, and eleventh grade levels. The study focuses on how textbook authors treat: (1) the background and historical setting from which the U.S. Constitution emerged; (2) the writers of the Constitution and the process they went through to produce it; (3) the descriptions of the Constitution's key provisions; (4) the issues involved in the ratification process; and (5) the extent to which the U.S. Constitution is depicted as a living document that has been amended over the years and continues to be the foundation of the government and nation. The study also focuses on how the Constitution is treated at different grade levels. Comparisons were made across textbooks at the same grade level and between the fifth and eighth grade levels. The findings were that the eighth grade textbooks offered more topics and subtopics, generally covered each topic in more detail, and reproduced the text of the U.S. Constitution accompanied by paraphrasing. The findings suggest that the treatment afforded the Constitution at grades five and eight is not sufficient and requires supplementary work by the teacher. The research also suggests that curriculum planners should take advantage of the opportunities at the three grade levels to help students develop their understanding from basic concepts in grade five to increasingly sophisticated concepts and principles in grades eight and eleven. (SM)