This issue of Development Dialogue is entirely devoted to the commemoration of Dag Hammarskjöld 40 years after his death. It contains the fourth Dag Hammarskjöld Lecture given by Kofi Annan, the Secretary-General of the United Nations, entitled ‘Dag Hammarskjöld and the 21st Century’. The Lecture is followed by three articles, which in different ways illustrate the broad cultural interests of Dag Hammarskjöld. Manuel Fröhlich writes about the correspondence between Dag Hammarskjöld and the English sculptor Barbara Hepworth; Marie-Noëlle Little gives the background to his correspondence with the poet and Nobel laureate, Saint-John Perse; and Bengt Thelin writes about Dag Hammarskjöld’s interest in nature. The three articles are preceded by a short introduction by Brian Urquhart.