Prepared by the National Research Council (NRC), this report on the contributions of science and technology to defend against terrorism is in the pre-publication form. Because the entire document is nearly 400 pages long, it is divided by chapter for easier downloading. The report begins with discussions of different kinds of threats that face the US, such as biological pathogens and nuclear and chemical weapons. Then, it examines more specific dangers to information technology, energy systems, transportation systems, and other infrastructure. The NRC draws conclusions about the current state of readiness, and offers some recommendations to improve what has already been established.