[en] The Columbia River System Operation Review (SOR) is being conducted jointly by the US Army Corps of Engineers, the Bureau of Reclamation, and the Bonneville Power Administration. This summary of the SOR story begins where the Draft EIS summary left off. It is divided into seven parts, each of which reports some aspect of the study's outcome: Part 1 is a history. The SOR was not a simple study on any level, and to understand the EIS alternatives, some background is necessary. Part 2 reports the major findings of the technical analysis of alternative system operating strategies, and presents the agencies' Preferred Alternative. Part 3 explains actions the agencies may take with respect to the Columbia River Regional Forum, the Pacific Northwest Coordination Agreement, and the Canadian Entitlement Allocation Agreements. Part 4 presents the Purpose and Need, elements at the core of any Federal EIS. It includes a map showing the Columbia River Basin and information on the affected Federal projects. Part 5 describes the substantial public participation and outreach that occurred during the SOR, and Part 6 summarizes efforts to incorporate the Tribal perspective into the study. Part 7 describes other activities that will be taking place in the next few years, which are related to and build upon the SOR