To solve two enduring problems in education--unacceptably large variation in learning opportunities for students across classrooms and little continuing improvement in the quality of instruction--the authors propose a system that centers on the creation of shared instructional products that guide classroom teaching. By examining systems outside and inside education that build useful knowledge products for improving the performance of their members, the authors induce three features that support a work culture for creating such products: All members of the system share the same problems for which the products offer solutions; improvements to existing products are usually small and are assessed with just enough data; and the products are jointly constructed and continuously improved with contributions from everyone in the system. (Contains 2 notes.)