Today a billion people, including about 340 million of the world's extreme poor, are estimated to live in 'fragile states'. This group of low-income countries are often trapped in cycles of conflict and poverty, which make them acutely vulnerable to a range of shocks and crises. This engaging book defines and clarifies what we mean by fragile states, examining their characteristics in relation to "weak" and "failed" states in the global system, and explaining their development from pre-colonial times to the present day. It explores the connections between fragile statehood and violent conflict, and analyses the limitations of outside intervention from international society. The complexities surrounding 'successes' such as Costa Rica and Botswana - countries which ought to be fragile, but which are not - are analysed alongside the more precarious cases of the Democratic Republic of the Congo, Afghanistan and Haiti. Absorbing and authoritative, Fragile States will be an invaluable resource for students and scholars of international relations, security studies and development.