Jim Dempsey and Fred Cate have compiled both a remarkable survey of surveillance practices around the world and a pragmatic framework of accountability and oversight principles that can protect human rights while defending national security. * U.S. Senator Patrick Leahy * We live in a world where data can help governments fight crime and terrorism, but that same data often resides in the hands of individuals or private companies governed by different national laws. With security, rights, and laws increasingly in conflict, this book couldnāt be more timely. * Brad Smith, President and Chief Legal Officer, Microsoft Corporation * The boundaries of what the State can, but should not do, is one of the most pressing legal, social, and ethical questions of our technology-driven age. If you want to gain a comprehensive insight into the complexities of this debate, this volume represents essential reading. * Giovanni Buttarelli, European Data Protection Supervisor *