This is a collection of original studies on the international health and welfare organizations between the First and the Second World Wars. The diversity of such organizations and their many-sided activities make this a rich and complex area of historical investigation that has direct relevance to current issues in international health. Multilateral organizations such as the League of Nations and a variety of types of non-governmental organizations are discussed. The role of scientific and professional factors, as well as the priorities of women's employment, eugenics and pronatalism are also considered.