The primary purpose of this report was to identify differential patterns of mathematics achievement which could be ascribed to different mathematics textbook series used by groups of pupils over a three-year span covering grades 4, 5, and 6. This volume is one of a series of reports of textbook comparison analyses in NLSMA. Comparisons are presented for six textbook series on 38 measures of mathematics achievement. The results support the conclusion that different patterns of mathematics achievement are associated with the use f different textbooks. "Two textbook groups appeared to stand apart from the remaining four as having been associated with generally high achievement." In addition to this report, "NLSMA Report No. 11" extends the analysis to grades seven and eight using other text series and different samples of X-Population students. (Author/FL)