The challenge Williams faces is that the question the book poses is not one especially amenable to being answered – certainly not after fifty-one years. Nevertheless, it is a worthy topic, not least because the Congo crisis has seen dramatic recent revelations, notably the extraordinary additional material, made public in 2006 and 2007, on Patrice Lumumba’s murder earlier in 1961. It is tempting to suspect that Williams was secretly hoping for a similar historical miracle to explain the other striking political death of the war – a miracle that did not arrive. That said, hers is the finest survey of what is available. Williams has tracked down almost every plausible lead, from myriad archives to intriguing informants, all the way to the field in Ndola. She tests these claims with a forensic eye, often informed by actual forensic experts. At one moment Williams stands tantalisingly close to a hangar that may contain the plane’s long-forgotten wreckage. It is fleeting, but electrifying.

The provocative question Williams cannot answer is less important than those slightly more pedestrian ones she does. In the course of trying to solve the practically insoluble problem of Hammarskjöld, the book reveals much about the politics of the Congolese disaster. Williams contextualises Hammarskjöld’s mission to the Congo with genuine élan. From the chaotic efflo-rescence of African decolonisation to the implications of Katanga’s secessionism, through to the (admittedly long) terminal phase of white rule in Africa, Williams carefully rebuilds the universe of 18 September 1961 as she wanders through it looking for the answer to Hammarskjöld. Quite apart from the shocking death of the Secretary-General, this was a period of rich dramatic potential in itself, exemplified by the fact that there was a multinational UN force actually engaged in combat, a phenomenon that has been exceptionally rare in the history of the organisation. Hammarskjöld has been memorialised in Zambia as someone who stood against white supremacy and imperialism. There are few memorials to other UN figures, especially recent ones.

Part of why Hammarskjöld’s death has attracted so much attention is due to the character of the man, and the United Nations he led. In the generally less than exciting pantheon of Secretaries General, Hammarskjöld stands apart as one of the more impressive figures. One struggles to see U Thant, Hammarskjöld’s immediate successor, flying in a small plane in the dead of night into a regional airport in Zambia, while UN-bannered troops were actively involved in fighting. He was not as ‘hands on’. Indeed, Thant’s solution to the problem of allegations of human rights abuses in the Soviet Union was simply to refuse the presence of UN hands on petitions and correspondence from Soviet citizens. The image of Hammarskjöld literally flying into the jaws of the conflict, with a small team of bodyguards, plotting a mid-course between West and Soviet, plays into the mythology of the organisation at its imperfect, but not yet utterly hopeless, best. This was a test of the United Nations, one Hammarskjöld embraced, with perhaps some level of reluctance. In a private letter, the Secretary-General opined, ‘it happens to be the Congo […] it happens to be now; it happens to be me’.

Williams doesn’t actually know who killed Hammarskjöld, only that someone did. While the title presupposes that his death was the product of some kind of conscious design and agency, she never manages to convince – and the proliferation of competing, candidate conspiracies never quite adds up to something persuasive. When Williams concludes, without deciding between the precise mode of assassination or criminal conspiracy, that the Secretary-General’s death ‘was almost certainly the result of sinister intervention’, it seems to overreach the evidence presented. The accretion of different theory after different theory does not strengthen the argument. As Brian Urquhart, one of the most senior UN officials in the Congo crisis, observed: ‘the main conspiracy theories put forward are mutually exclusive – if one is true, all the others must be false.’ The rough parity accorded to most of the theories presented, the more fantastical ‘Operation Celeste’ notwithstanding, tends to harm, rather than strengthen, her case.

It would have been better to rein in the claim, as was done in the original 1962 UN investigation report, which delivered an open finding, while explicitly including the prospect of assassination. Who May Have Killed Hammarskjöld is less compelling, but the story of the Congo crisis is important, not solely, or even primarily, because of the death of the Secretary-General, as tragic and shocking as it was. As Williams acknowledges, the history of this period deserves study, because it reveals how Cold War and commercial imperatives were shaping (and warping)
the politics of Africa in the revolutionary and plastic moments of decolonisation. Hammarskjöld’s death is an elegant vector for charting a way through this history, but its importance resides beyond him.