Does development research need reinventing? If it does, why now and in what ways? These are the questions addressed by the papers in this issue of the IDS Bulletin, many of which were presented at IDS Fortieth Anniversary Conference in late 2006. They were also asked by the 46 Roundtables held throughout the world in 2006, organised by IDS partners and alumni, which preceded and helped frame the Conference agenda. Much is changing in 'development' and its political context. International development issues are becoming more global; inequality, capacity to use and generate knowledge, China's emergence altering Western assumptions, new sources of financial capital, information shared through the internet, new transnational alliances, sustainable development, consciousness in the West about living conditions in other countries, shrinking spheres of influence of the aid donors, and the blurring of boundaries between domestic and international policies.

Development research has constantly reinvented itself over the years, but for those involved in the IDS40 activities there was a sense that there is a need for development research to make a conscious decision to change direction. In the West, one's fortieth birthday is known as a watershed year - an ending of one phase of life and a beginning of another. But in many countries the fortieth birthday signals a very different kind of transition as one draws closer to the end of life expectancy. It is natural therefore to reflect on how much has changed in the world since IDS was founded in 1966 and to characterise the above changes as some kind of fork in the road or threshold for development and therefore for development research.