In the early hours of 1 October 1965, a group of junior Indonesian Army officers, supported by the clandestine Special Bureau of the Indonesian Communist Party (PKI), kidnapped and killed six top army generals. The remainder of the army high command rallied around Major General Suharto, and using this movement as pretext, orchestrated the mass arrests and disappearances of hundreds of thousands of PKI supporters. Crushing the communist party was the heroic myth underpinning the legitimacy of the New Order regime of Suharto; yet the nature of that crushing, the mass execution of bound detainees in remote areas, remained outside the regime's official history. The relative silence surrounding the killings has been so pervasive that for decades historians have debated whether the killings were due primarily to the top-down machinations of the Indonesian Army, or the bottom-up expression of civilian grievances. This debate was resolved in 2018 with the publication of two landmark works by Jess Melvin and Geoffrey Robinson that firmly establish the army as the organiser of killings across the archipelago.

John Roosa's most recent book Buried Histories: The Anticommunist Massacres of 1965–66 in Indonesia represents a new wave of scholarship on the Indonesian Killings that takes the leading role of the army as a given. The book attempts to answer three questions: How could the PKI be victimised in such numbers? What were they thinking and doing at the time of the army attacks? And how could the PKI be crushed so quickly, and with such little resistance? (p. 21). Drawing on a rich range of oral interviews, this book reconstructs details from massacres in four areas: Surakarta, Bali, South Sumatra, and Riau.

Buried Histories makes three major contributions to our understanding of the Indonesian Killings. First, it offers significant evidence as to why the PKI was caught so unprepared for army repression: PKI leaders believed their ability to build communist support within the armed forces would blunt any direct action taken against the party. Roosa highlights how the PKI ought to have been more concerned with the army's ability to transform itself into a parallel state apparatus in the years preceding the massacres. Second, the book showcases the interaction between local governors, commanders, anticommunist civilian organisations, and the army high command in each of its four case studies. In doing so, Roosa moves from the question of who was most responsible for the violence as a totality to who advocated for, participated, and was targeted in each set of massacres under study. Finally, and most significantly, Roosa provides the most detailed description of anindividual massacre to date. Doing so has made visible events intended to forever remain secret.

The first chapter of this book traces the expansion of the Indonesian Army's territorial command structure, as well as the PKI's strategy of mobilising support from peasants, workers, and the military. Roosa draws attention to the army's ability to create a parallel state apparatus designed to check the growth of the PKI and eventually crush it when provided the opportunity. This chapter also highlights the importance of the mass media in Indonesia, as well as Sukarno's mastery of radio to connect directly with the Indonesian populace.

Chapters 2 and 3 focus on the Indonesian Army's disinformation campaign to frame the PKI as a demonic entity that needed to be purged from sociopolitical life. Chapter 2 examines the army's propaganda, which transformed the kidnapping of six generals into a massive PKI insurgency intended to seize power and murder its opponents, while chapter 3 focuses on the use of torture to bring this fictional insurgency to life through pain inflicted on the bodies of thousands of civilians with no knowledge of the kidnappings in Jakarta. The army's seizure of and monopoly over the mass media, Roosa argues, helped to demobilise resistance to the ongoing campaign of mass murder.

Chapters 4 through 7 reconstruct the massacre of prisoners in Surakarta, Bali, South Sumatra, and Riau. Each chapter reconstructs the local history of the PKI, that of their opponents, reactions to the putsch in Jakarta, and the eventual massacres of prisoners. The detailed reconstructions in these chapters are a major achievement. In the case of Surakarta, Roosa is the first to unpack how the PKI's Special Bureau brought together sympathetic officers to seize the city following the movement in Jakarta. Bali is the subject of two chapters, with chapter 6 reconstructing the details of a single massacre that occurred in Kapal. It is easily the most detailed reconstruction of a massacre to date, and highlights that while officially secret, massacres such as this were witnessed by communities, provincial leaders, and military commanders. South Sumatra and Riau are examined in tandem, highlighting how differences in intra-army politics led to vastly different levels of killing. Of all the cases examined in this book, only in Riau was the local commander sufficiently entrenched to successfully resist orders to massacre the population of political prisoners under his care without being replaced. This focus on intra-army splits, especially below the divisional (Kodam) level, is a needed addition to understand the regional patterns of violence. Woven through each chapter is a series of deeply moving personal stories, bringing the human tragedy of the killings to the forefront, and restoring a sense of agency to civilian victims of military repression.

Buried Histories is a significant achievement and a major contribution to our understanding of Indonesia's anticommunist massacres. Scholars of Indonesian and Cold War history, of genocide, and of political violence will find this book to be a great resource. It is also an exemplary work of oral history that would fit well on a graduate syllabus. In this book Roosa gives voice to the voiceless, and readers will experience both significant scholarship and a passionate challenge to the Indonesian state's status quo of silence and denial of its recent history.