This handbook offers a comprehensive set of practices and mechanisms which might shape parliament's contribution to security oversight. It has been written on the assumption that there is no single model of parliamentary oversight which works for all countries. The rules and practices that are accepted and effective in one place may be unthinkable or irrelevant in another. Moreover, all parliaments do not have the same powers. Given these different realities, some of the suggestions the handbook contains may inevitably appear excessively idealistic. At the same time, the complex nature of security issues makes it impossible to treat all aspects in a single volume. The handbook should therefore be seen as a broad introduction to enhancing parliamentary oversight of the security sector which - it is hoped - will encourage the reader to carry out further research.