Executive Summary Background: Following the aftermath of the major power system blackouts of 2003 (in Sweden/Denmark, Italy, London and the eastern United States and Canada), the IEEE Power System Dynamics Performance Committee (PSDPC) sponsored an all day panel session on blackouts, at the Power Engineering Society General Meeting in Denver, Colorado, in 2004. Subsequent to this panel session, the PSDPC formed this Task Force. Since 2004, the Task Force sponsored another panel session (at the Power Systems Conference and Exposition in Atlanta, Georgia in 2006) and also sponsored the publication of a series of invited papers on the subject of blackouts in the September/October issue of the IEEE Power & Energy Magazine. This report constitutes the final deliverable of the Task Force. The aim of this document is to provide a single, comprehensive, source of information to the industry covering the major system dynamic performance aspects of power system blackouts. The document covers in detail, the following subjects: 1. A comprehensive review of most major power system blackouts and large system disturbances in the past four decades, worldwide. The focus is primarily on the system dynamic performance issues, however, the descriptions of these events highlight all of the apparent root causes and lessons learned by the industry in their aftermath. 2. A comprehensive review of best practices for improving power system dynamic performance and thus minimizing the risk of wide spread disturbances and subsequent blackouts. 3. A review of existing and emerging modern technologies that can help to improve system dynamic performance and thus help to minimize the risk of blackouts. Each of the three chapters of the report contains a detailed summary and conclusions section that provides the main conclusions of that section as well as pertinent recommendations (most notably in Chapter 2 a summary list of best practices is provided in the chapter summary). Below the overall high-level conclusions and recommendations of the report are presented.