BOSTON — The last years of this century have seen the best of days and the worst of days: from the jubilant fall of the Berlin Wall to the brutalities of ethnic cleansing in Bosnia, from the exhilarating end of apartheid in South Africa to horrific massacres in Rwanda. Even as people rejoiced in the many victories over oppressive regimes, they were jolted by the reminder that human beings are still imprisoned by the sense of "differentness." And that the capacity of groups of people to disparage other groups, when played upon, can engender acts of cruelty and injustice. If not dealt with appropriately, those acts, in turn, foster a desire for vengeance, a tit for tat that divides communities and nations and tears the fabric of individual lives. When those acts take the form of mass cruelty or atrocities, they stun the sensibilities. Some 6 million Jews and 2 million Cambodians starved or executed; 20,000 Bosnian women raped; thousands of Argentinians "disappeared," many thrown out of airplanes into the ocean. What is to be done? In the face of such events, ordinary individuals often feel helpless. Stopping the pattern of vengeance Yet the mark of this century is not in any uniqueness in atrocities, says Martha Minow, a professor at Harvard Law School, but in the way ordinary people have helped bring about responses to such tragedy that seek to avoid a pattern of vengeance in the future. "If there is an accomplishment in this area during this century," she says in an interview, "it is the creation of a movement for human rights. And that movement, unlike any other kind of legal movement, depends on the consciousness of ordinary people ... their ideas, ideals, and commitments." The flip-flop two weeks ago by Cambodian leader Hun Sen, she says, "is a testament to this emerging human rights consciousness." When two of the Khmer Rouge leaders most responsible for atrocities of the 1970s surrendered recently, Hun Sen at first called for "digging a hole and burying the past." But immediately, he was forced to recant and call for a trial, because of the response of his own people and the world. People, she adds, now "look at a situation such as Cambodia's and say, 'There is something you could be doing to bring the facts of the past to light, to call perpetrators to account, to undertake a resolve to never let such things happen again. Failing to do that is an insult to the memory of those who died.' " The international tug-of-war over former Chilean strongman Augusto Pinochet reflects that same demand for accountability. Dr. Minow's new book, "Between Vengeance and Forgiveness: Facing History after Genocide and Mass Violence" (Beacon Press, 1998), skillfully explores what steps can be taken in the wake of mass atrocities. From trials and international tribunals to truth commissions, reparations, and other forms of public acknowledgment and truth-telling, she shows how each type of response, with its particular benefits and limitations, has served valuable purposes in various circumstances - and why none alone is ever adequate to the overall needs for healing and reconciliation. In the aftermath of mass violence, full justice is never possible, she says. How, for instance, could Rwanda ever prosecute all those responsible for its tragedy? Trials are selective. They get at justice in the case of a few, but never reveal the whole story. Truth commissions may accomplish that, but is justice done without prosecuting those found to be responsible? When an atrocity occurs, societies must decide which of several needs for response take priority. One very crucial need, Minow says, is acknowledgment - "public acknowledgment and fact-gathering joined together so that there cannot be denial, and so there is incorporation into national and international memory of what happened." Broadcasting testimony "The broadcasting of testimony by both survivors and perpetrators [before South Africa's Truth and Reconciliation Commission] helped to crack a kind of wall of denial in that country," Minow says. A second need is accountability - to trace responsibility to individuals so that there is not a blaming of a whole people. A third aim is to "help support the emergence of a human rights culture and democratic culture in the particular locality," and a fourth, "to help produce a stable government and society that entrench respect for human dignity." Yet there is tension among these purposes, she points out. "To focus on accountability may point to trials, yet trials may jeopardize the stability of a fledgling democratic government." In Argentina, a truth commission in the 1980s uncovered military responsibility for the disappeared in the "dirty war," but the new democratic government's efforts to follow through were aborted by rumbles from the barracks. Amnesty followed. Yet Argentinians never forgot - the "hunger for accountability" remained. When two military men were recently arrested for the kidnapping of "disappeared" pregnant women and snatching of their children for adoption, "the public response was one of extraordinary gratitude: Major newspapers said, 'God lives!' and people cried in the streets," Minow says. Similarly, Chile's discomfort over the detainment of General Pinochet in Britain is due to unfinished business in that country over past atrocities. Stability and amnesty have had priority over accountability. A governmental amnesty is forced upon people, Minow points out. Forgiveness is "a choice held by individuals who were victimized.... If it's ordered, it doesn't have the qualities of a choice or grant that make it so wondrous." "The challenge for governments and institution builders," she adds, "is to come up with a way between this forced forgiveness, which doesn't work, and vengeance, which is devastating and can unleash further waves of violence." Treading social context In her incisive and insightful book, Minow shows how important the political and social contexts are to the choices a society makes in treading "the path between too much memory and too much forgetting." South Africa has been able to go beyond what others have done with truth commissions for several reasons: its peaceful transition of power that gave the country back to the majority; a strong tradition with deep African and Christian roots that views justice as a community concern, and inclusion of the offender as part of the task of justice; an amnesty that was not a blanket one, but a one-by-one application process that also required testifying. The commission itself was designed by a public process, Minow says, "emerging from parliamentary activity, discussions in rural areas and in urban church centers. It thus helped express and consolidate the new democratic government." It allowed people from all walks of life to tell their stories, promoting catharsis and healing, and it described the role of many sectors of society in apartheid, reframing the country's historical narrative. Whether it will contribute to national reconciliation remains an open question. Minow assesses many other avenues for pursuing healing and reconciliation, such as apology and reparations (including the Japanese-American experience); building new institutions; works of the artistic imagination; creating days of memory (Australia's "Sorry Day," a national apology for abducted and adopted Aboriginal children); and public debate and education. A public education dimension in relation to each of the responses to mass violence is as important as the responses themselves, Minow says. "Young people should have exposure to the degrees of violence adults have committed, often at the expense of children, and also to the struggles to come up with responses. We should give them some tools to begin to address what we find difficult, and not leave them with despair," she says.