The private business sector suffered both directly and indirectly from the terrorist strikes of 11 September 2001. Many business workers perished in the New York World Trade Center, and the insurance, transport, and tourism industries were hard hit by the aftermath. Restrictions imposed in thename of security made business travel and the movement of goods more complicated. The private sector was called upon to support the fight against terrorism actively with tougher controls on money transfers and on the export of dangerous materials and technologies.These events offered a striking case of the growing interdependence of the private and public sectors in tackling present-day security challenges. The impact of the private sector, for good or ill, in areas of conflict has long been recognized. Private business is at the centre of the latestconcerns over the vulnerability of crucial infrastructures, including energy supply. Systematic public-private sector consultation and partnership are needed to tackle these problems, but neither the principles nor comprehensive mechanisms for such cooperation have yet been identified.This book brings together reflections on general and specific aspects of public-private sector interaction, from a variety of experts in business, government, international organizations, and the academic world. For completeness and balance, it also enquires into the costs of security and includesperspectives from Africa and the Arab world. It offers new reference material to help in the further exploration of this important subject.