Ever since the publication in 2004 of the 9/11 Commission Report, the U.S. intelligence community has been in the throes of a convulsive movement for reform. In Uncertain Shield, Richard A. Posner continues the story of the reform movement begun in his earlier book, Preventing Surprise Attacks. Analyzing the latest decisions made by the Director of National Intelligence and examining in detail issues from Hurricane Katrina to the national security computer networks, he demonstrates the dangers of an overly centralized intelligence system and offers clear ideas for reform that go beyond risky organizational changes.