This document was created in response to a request from the Wisconsin Department of Public Instruction to the Wisconsin Minnesota Comprehensive Center (WMCC) Region 10 to provide information on high-quality, qualitative studies about K-2 explicit, systematic phonics instruction. This document is intended to supplement the review document: "Explicit, Systematic Phonics Instruction." This document contains additional resources and theories that may be useful in creating a comprehensive K-2 reading program. It is meant for internal use by the Department of Public Instruction to inform professional development provided to Wisconsin districts, schools and appropriate stakeholders. [For the original review, see ED612073.]