The Adelphi Papers monograph series is the International Institute for Strategic Studies' principal contribution to policy-relevant, original academic research. Collected on the occasion of the Institute's 50th anniversary, the twelve Adelphi Papers in this volume represent some of the finest examples of writing on strategic issues. They offer insights into the changing security landscape of the past half-century and glimpses of some of the most significant security events and trends of our times, from the Cold War nuclear arms race, through the oil crisis of 1973, to the contemporary challenge of asymmetric war in Iraq and Afghanistan.