This book provides a key reference on the role of the Commonwealth and its member states in relation to international humanitarian law (IHL). It provides insights in the implementation of IHL in Commonwealth states and, particularly, the challenges faced by small states. It examines the progressive development of IHL in the Commonwealth and provides an analysis of some of the landmark decisions emerging from the Special Court for Sierra Leone. The book was developed collaboratively between the Commonwealth Secretariat and the International Red Cross and Red Crescent Movement. In this regard, it contains insights in the work of the Secretariat with regard to implementation of IHL and an assessment of legislation enacted by Commonwealth states as well as an accession chart to IHL instruments. It expounds on the work of the Movement, including the role of National Societies, the International Humanitarian Fact-Finding Commission, and the development of international disaster response law, rules and regulation. This book was based on a special issue of Commonwealth Law Bulletin.