A new fourth edition of is on its way and will be available for review in late spring, in plenty of time for fall course adoptions. Recent judicial rulings, legislative initiatives, and executive reforms are prominently featured. They help refine our understanding of relevant government structures, processes, and institutions, and they raise critically important new questions. They also address new threats and breathtaking advances in technology. The election of President Donald Trump has brought dramatic changes in executive branch decision making, too. These developments are reflected here, as well, including some that became available just days before the new book went to press. This study of counterterrorism law is both comprehensive and self-contained. As in prior editions, we have organized the materials in this book into functional categories in order to facilitate study and to help put new developments in the field into perspective. This is not a “how-to-do-it” course, however.