Dr Philip Thornton is based in Edinburgh, UK and works with the International Livestock Research Institute in Nairobi, Kenya, and the University of Edinburgh. His activities embrace systems characterisation and analysis, ex post and ex ante impact assessment, a wide variety of systems modelling, poverty mapping, and vulnerability assessment. He completed a BSc degree at the University of Reading, UK in 1979, specialising in agricultural systems. Dr Thornton earned his PhD degree, that involved the interface between biophysical and socio-economic models, a general area that has been a major interest ever since, in farm management (1983) from Lincoln College, New Zealand. He spent three years as a Post-Doc at the International Center for Tropical Agriculture (CIAT) in Colombia, working on bioeconomic modelling of livestock production systems in Latin America, and then three years based at the University of Edinburgh on crop and household modelling projects in Central America and southern Africa. In 1990, he joined the International Fertilizer Development Center in Alabama, and was involved in projects in various countries in Latin America, Africa, Asia and Eastern Europe. He started with ILRI-Nairobi in 1996. He serves on the Board of Directors of the Soils Management Collaborative Research Support Program (CRSP) and of the International Consortium for Agricultural Systems Applications (ICASA), and is Editor-in-Chief of the journal Agricultural Systems. In the SLP, Dr Thornton led work on poverty mapping and impact assessment of maize improvement. He is currently involved in the development of a framework to assess ex-ante the impact of improving feed resources in crop–livestock systems.