From New York to Cape Town to Sydney, the bronze body doubles of the white men of empire—Columbus, Rhodes, Cook—have lately been pelted withfeces, sprayed with graffiti, had their hands painted red. Some havebeen toppled. The fate of these statues—and those representing white men of a different era, in Charlottesville andelsewhere—hasignited debate about the political act of publicly memorializing historical figures responsible for atrocities. But when the statues comedown, how might the atrocities themselves be publicly commemorated, rather than repressed?

In the course of her long career, the historian Lyndall Ryan has thought about little else. In the late nineties and early aughts, Ryan found herself on the front lines of what came to be known, in Australia, as the History Wars: skirmishes fought with words, source by disputed source, often in the national media. At stake was whether the evidence existed to prove—as Ryan and others had argued, and conservative historians and politicians refused to accept—that Indigenous Australians had been massacred in enormous numbers during colonization, from late inthe eighteenth century to the middle of the twentieth. Even among those who grudgingly accepted that there had been widespread killings, there were still bitter, and, in some cases, ongoing, fights over the exact number of Indigenous people killed, the strength of their resistance to British settlement, and the reliability of oral versus written history. A truce has never been reached in what the Indigenous writer Alexis Wright calls Australia’s entrenched “storytelling war.” (In October,Prime Minister Malcolm Turnbull rejected the core recommendations of the government-appointed Referendum Council,which, after six months of deliberative dialogue across Aboriginal and Torres Strait Islander communities, had called for establishing an Indigenous voice to Parliament, and a process of “truth-telling about our history.”)

In 2005, in the midst of the public disputes over Australia’s history, Ryan came across the work of the French sociologist JacquesSémelin. After the Srebrenica massacre, in 1995, there was renewed interest from European scholars in understanding massacre as a phenomenon. Sémelin defined a massacre as the indiscriminate killing of innocent, unarmed people over a limited period of time, and he characterized massacres asbeing carefully planned—i.e., not done in the heat of the moment or the fog of war—and deliberately shrouded in secrecy by the systematic disposal of bodies and the intimidation of witnesses. Sémelin’s typology prompted Ryan to reconsider her own earlier scholarship on the Tasmanian War, which was waged between British colonists and Aboriginal peopleearly in the nineteenth century. This time, Ryan concluded that there were not four massacres of Indigenous people but, in fact, more than forty. ...