"Saxon Math" curricula and materials are available for grades K through 12, with the content and skills designed to meet National Council of Teachers of Mathematics (NCTM) standards and various state standards. This WWC report focuses on middle school math curricula, defined as all Saxon Math curricula for grades 6 through 9. The sixth-grade curriculum covers simplifying expressions containing parentheses, graphing functions, and understanding ratios and proportions. The seventh-grade curriculum covers pre-algebra topics such as rate, powers, roots, and geometric proofs. The eighth-grade curriculum covers all topics usually taught in pre-algebra in addition to topics from geometry and discrete mathematics. The ninth-grade curriculum covers all topics usually taught in a first-year algebra course (such as exponents, roots, and algebraic word problems) as well as conceptual understanding, procedural fluency, strategic competence, adaptive reasoning, and productive disposition. "Saxon Math" curricula for the elementary schools are reviewed in the WWC Saxon Elementary School Math intervention report. One study of "Saxon Middle School Math" met What Works Clearinghouse (WWC) evidence standards, and five studies met standards with reservations. The six studies included over 5,300 students in sixth to ninth grades from over 70 schools in Georgia, Missouri, Mississippi, Nebraska, Oklahoma, and Texas. Saxon Middle School Math was found to have positive effects on math achievement. (Contains 41 footnotes and 1 appendix on study characteristics.) [The following study is reviewed in this intervention report: Williams, D. D. (1986). "The incremental method of teaching algebra." Kansas City: University of Missouri.]