This report draws on the findings of nearly four dozen others: national and international studies that speak with a strong, collective voice about what it takes to improve math and science education. But the authors' intent with "World Class" is not simply to synthesize those reports. It is to establish a statewide, working agenda for Massachusetts--a blueprint for how to enact the cumulative recommendations of the researchers and educators mentioned in this paper. This report is also a K-12 public education companion to the report issued last year by Mass Insight Education's sister organization, Mass Insight Corporation. "Choosing To Lead: The Race for National R&D Leadership" and "New Economy Jobs" presented an action plan to help Massachusetts maintain its position as a sci-tech leader and to secure its economic future. The recommendations offered by the researchers and educators are: (1) Invest in Massachusetts' Teachers of Math and Science by: (a) Preparing new teachers for higher math/science expectations; (b) build the capacity of current teachers; and (c) enhance the status of the teaching profession; and (2) Invest in Massachusetts Students' Math/Science Experience by: (a) challenging all students with rigorous curricula; (b) engaging students in active, inquiry-based STEM experiences (Science, Technology, Engineering, Math) to build interest in STEM-related careers; and (c) expanding parent and public understanding of the critical importance of STEM to the state's economic future. Appended are: (1) Content Knowledge, Pedagogical Knowledge, and Pedagogical Content Knowledge; and (2) Curriculum, Instruction, Assessment. [This report was prepared with Arthur Eisenkraft and Hannah Sevian.]