In many ways, writes historian Dan Stone, “we have failed unflinchingly to face the terrible reality of the Holocaust”. His remarkable book offers both a narrative overview and an analysis of the events, challenging many common assumptions and often returning to how this terrible history remains “unfinished”. Some recent scholarly studies of the Holocaust, Stone argues, have stressed “the reactive nature of German decision-making, driven primarily by military circumstance”. He does not dispute the importance of contingent factors, such as rivalries between different Nazi factions, or how the leadership ramped up the level of persecution after the public largely failed to object to the Kristallnacht pogrom of November 1938 and then the T-4 euthanasia programme. But he also puts a firm emphasis on “ideology, understood as a kind of phantasmagorical conspiracy theory, as the kernel of Nazi thinking and action”. Another issue Stone addresses head on is the sheer variety of Nazi brutality. The Holocaust is sometimes seen as “characterised by the modern efficiency of factory-line murder”. In reality, as the book makes clear, such “industrial genocide” was accompanied by “huge numbers of Jews [who] were shot in face-to-face killings reminiscent of colonial massacres, albeit on a vast scale” or “in ghettos, where they were starved to death”. Even Auschwitz was “low-tech, partly built on scavenged materials”. A powerful chapter explores what happened when the war ended. Liberation, claims Stone, “needs to be understood in inverted commas: many survivors died soon afterwards, too ill to be helped, and many more, amazed to have outlived the Nazi regime, were shocked to discover that they remained captive, unable to go where they wanted” – the last displaced persons camp was not closed until 1957. Jews who managed to return to homes in western Europe found their suffering and stories “subsumed into official narratives of resistance, patriotic sacrifice and national solidarity”. For most east European Jews, “home no longer existed”. Though prewar Jewish politics were “remarkably varied”, as Stone points out, it is hardly surprising that “Zionism prevailed” in the DP camps, where inmates “felt rejected by Europe, which they rejected in turn”. Although the Holocaust was obviously initiated by Germans, it was very much “a continent-wide crime” and found willing and often enthusiastic collaborators right across Europe. Such people, according to Stone, were motivated by “greed, nationalist aspirations and ideological affinity with Nazism”, but he also points to “the disturbing fact… that many perpetrators appear to have taken part because they enjoyed doing so”. This may not be news to historians, but many countries, particularly in post-communist eastern Europe, have been slow to acknowledge their level of complicity. Recent national commissions of inquiry have shed valuable light on this troubling history, but they have also bred what Stone calls “the ressentiment” that is “one of the roots of the revival of fascism in Europe today”. A 2018 law made it “a criminal offence to accuse Poles of being complicit in the Nazi murder of the Jews”. According to a scholar called Jan Grabowski, he and his fellow “independent historians of the Shoah continue to face today, in Poland, the full might and wrath of the state”. Nationalists in post-communist eastern Europe have understandably emphasised the appalling atrocities committed by the Soviet Union. But Stone flags up the way this is sometimes linked to the notion that communism was “a ‘Jewish’ ideology” brought into the region from outside, implying that the Holocaust can be seen in this light as “a justifiable response”. As this may suggest, Stone is sceptical about the oft-proclaimed benefits of Holocaust education and commemoration. Back in the 1990s, he believes, awareness of the Holocaust was not only widespread but “channelled in favour of human rights, cosmopolitanism and progressive ideas”. Since the millennium, however, “this confident narrative has been derailed. The use of Holocaust memory to further nationalist agendas, to facilitate geopolitical alliances on the far right or to ‘expose’ progressive thinkers for their supposed antisemitism or anti-Israel bias is now a familiar part of the landscape.” The implications of all this could hardly be more sobering. Just as “Nazism was the most extreme manifestation of sentiments that were quite common, and for which Hitler acted as a kind of rainmaker or shaman”, suggests Stone, the defeat of his regime has left us with “a dark legacy, a deep psychology of fascist fascination and genocidal fantasy that people turn to instinctively in moments of crisis – we see it most clearly in the alt-right and the online world, spreading into the mainstream, of conspiracy theory”. His book offers a brisk, compelling and scholarly account of the Nazi genocide and its aftermath. But never for one moment does it let us believe that the events are now safely in the past. The Holocaust: An Unfinished History by Dan Stone is published by Pelican (£22). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply