For more than forty years, Brian Abel-Smith, a health economist and political adviser, was closely involved with the development of health and social welfare policies worldwide. From his seminal research with Claude Guillebaud on the cost of the British National Health Service in the 1950s, he quickly developed an international reputation as a consultant who could be relied upon to produce useful reports with speed and efficiency. His research centred on the determinants of health, health service planning and financing, population control and poverty. He pioneered international comparisons on health services finance for the World Health Organisation in 1958, and completed numerous assignments in over 80 countries - ranging from short reports to (in the case of Mauritius) the creation of a fully-fledged social welfare system. From 1983-86 he was senior adviser to the WHO Director-General Halfdan Mahler on the economic strategy for the Health For All (by the year 2000) programme. This talk will use Abel-Smith’s biography to explore wider issues of how international organizations like the WHO solicit advice from external consultants, how networks of knowledge develop, and the capacity of individuals to effect change within global systems. This seminar took place at Oxford Brookes University on 18 October 2011