This book began life as a doctoral thesis. I originally expected the thesis to focus less on the UN Security Council's sanctions practice and more on theoretical questions arising from the Council's application of sanctions. However, early in my research I discovered that most books on UN sanctions analysed sanctions from a broad policy perspective and did not pay too much attention to the finer print of the provisions of Security Council resolutions that establish and modify each UN sanctions regime. Although there were valuable studies of this type concerning individual sanctions regimes, there was no central source tracing the evolution of the Security Council's many sanctions regimes. I thus began to prepare the summaries of UN sanctions regimes that feature in Appendix 2. Once I had completed these summaries, I moved on to the challenging assignment of describing and analysing the contours of the UN sanctions system.

Just as I did not originally set out to describe the UN sanctions system, neither did I intend to explore the relationship between those sanctions and the rule of law. I had planned to analyse the legitimacy of sanctions, which I still consider to be an extremely important theme. But on 24 September 2003 I witnessed a Security Council debate on justice and the rule of law, culminating in the adoption of a Security Council presidential statement affirming the vital importance of the rule of law in the Council's work.