In 2003, the President and the U.S. Congress established the Department of Homeland Security. From the beginning, its mission was clear: prevent terrorist attacks, protect against threats to America's safety and security, and prepare the nation to respond effectively to disasters, both natural and man-made. This monumental mission demands a comprehensive strategy. It also requires a crystal-clear explanation of that strategy to Americans and their allies worldwide. In a revealing new book, Homeland Security: Assessing the First Five Years, Michael Chertoff provides that explanation. In a refreshingly candid and engaging manner, America's former homeland security secretary depicts the department's long-term approach, what it has achieved, and what it has yet to do.The strategy begins with the threats America faces, from terrorist groups like al Qaeda to hurricanes like Ike or Gustav. "Once these threats are identified," Chertoff writes, "we can confront them, using every tool at our disposal. We can stop terrorists from entering the country, and discourage people from embracing terrorism by combating its lethal ideology. We can protect our critical assets and reduce our vulnerabilities to natural disasters. We can plan and prepare for emergencies and respond in a way that minimizes the consequences. And we can work closely with our allies abroad to reduce the risk of future disasters." In each of these areas, Chertoff informs the reader what the nation has done and what it still must do to secure its future.How well has this strategy fared in a post-9/11 world? Since that fateful day, there have been no global terror attacks on American soil. Yet in the face of continued dangers, Michael Chertoff warns repeatedly against complacency. He urges America and its leaders to strengthen their resolve, stay the course, and build creatively on past successes.