Reading selections from six Scholastic Aptitude Tests (SAT) administered from 1947 to 1975 were analyzed to determine whether a decrease in the difficulty level of elementary and secondary textbooks, workbooks, and teachers' guides corresponded with the SAT score decline. Various indices of reading difficulty and challenge were used. Readability analysis of the SAT passages revealed generally decreasing difficulty from the stable years (1947 and 1955), through the pivotal year (1962), to the declining years (1967, 1972, and 1975). A possible gap between the difficulty of the SAT passages and eleventh grade textbooks was indicated. The SAT passages were the most difficult of any of the materials analyzed, with difficulty levels ranging from grades 11 to 15. The eleventh grade texts in history, literature, grammar, and composition had an average readability level of grades 9 to 10. There are signs of a recent increasing challenge in the textbooks, particularly at the elementary level; but in both elementary and secondary instructional materials, there has been particularly little change in writing activity. The assignments in reading, history, and literature textbooks generally require underlining, circling, and filling in of single words. Few assignments ask students to write a paragraph, story, letter, or theme. (Author/EVH)