The purpose of this report is to document the development of the McREL Approach for those interested in school improvement. This document builds upon an earlier intensive site report (McIver & Dean, 2004) and the preliminary McREL Approach report (Dean, 2004). The first section describes the McREL Approach framework, which includes six stages for assisting sites in acquiring the knowledge and skills they need to lead school improvement and sustain their improvement efforts for the long term. The author then details how McREL staff tested their initial theories about assisting low-performing schools and includes lessons learned from the application of these ideas in sites in South Dakota and Kansas. The author then describes the next steps in applying the McREL Approach. The Development of the McREL Approach is appended. It provides background information on the research that underlies this school improvement process.