Peace and security are international public goods, but have traditionally been the preserve of state actors. This is changing. An increasingly vocal global civil society is emerging, as new challenges and conflicts test conventional, state-based approaches to preventing and resolving war. Civil society actors now play multiple roles in maintaining peace and security – early warning, identifying neglected conflicts, formulating policy responses, mobilizing public opinion, even directly assisting peace talks. Philanthropy has proven indispensable to civil society’s influence and its ability to pursue a global public good. Louise Arbour will examine public interest diplomacy, and the crucial roles of civil society and philanthropy in maintaining peace and security. Before being named President CEO of the International Crisis Group, she served as United Nations High Commissioner for Human Rights, as well as the Chief Prosecutor for the International Criminal Tribunals for the former Yugoslavia and for Rwanda.