Within months since its publication, this book justified its appearance through the remarkable degree to which it resonated in the international public sphere. Not surprisingly so, it triggered a partly controversial debate over the issue it dragged out of the closet. Williams presents systematic efforts to fuel the ongoing speculations 50 years after the death of the United Nations’ second Secretary-General, although it does not answer the title's suggestive question. Hammarskjöld was on board a DC6, which crashed while approaching Ndola airport in the night from 17 to 18 September 1961. None of the 15 members of his entourage and the crew survived. A bodyguard still alive for a few days (who might have been saved if properly taken care of) was among the witnesses, whose testimonies ever since then – to put it mildly – provide food for thought.

In the absence of a ‘smoking gun’, evidence remains inconclusive. But it is the merit of Susan Williams, a Senior Research Fellow of the Institute of Commonwealth Studies at the University of London, to present the hitherto most detailed effort challenging the tendency of several official investigations, all including a pilot's error as a likely cause for an accident. Williams nurtures suspicions of a different nature, raised ever since the crash outside the mining town in the Northern Rhodesian copper belt. Hammarskjöld was on his way to meet Moise Tshombe, the leader of the secessionist movement in neighbouring Katanga, to seek a solution to the impasse in the Congo.

The Congo then was as much as today an attractive prey for exploiting the mineral wealth. Governments, mining companies, intelligence agents, mercenaries and all other sorts of dubious ‘entrepreneurs’ in combination with hard core racists in defence of settler colonialism created a toxic, at times lethal mix. This is the stuff, which John le Carré turns into bestselling agent thrillers close to reality. Williams’ account seems not far from le Carré's plots, but offers in a non-fictional manner discomforting insights into the forces seeking to pursue their interests – at times at all costs. Following the revelations by Ludo de Witte on the assassination of Patrice Lumumba, more than a decade later Susan Williams adds some light on another chapter of the Congolese ‘heart of darkness’.

This pioneering book plays an important role as catalyst for a necessary reassessment. What is missing, however, is a sufficiently comprehensive, analytical contextualization of the role Dag Hammarskjöld and the United Nations played in the Congo and other cases of decolonization, which was not to the liking of the big powers. The official UN commission of enquiry was at the time careful not to exclude other reasons than human failure – including external factors – as a possible cause of the crash. This book offers enough to strengthen the efforts to bring about another United Nations enquiry into the circumstances of the crash – an initiative, which the resolution adopted half a century ago by the General Assembly after submission of the official report by the commission explicitly made provisions for in the case of new evidence.