This publication provides policy, methodological, legal and operational guidance based on relevant international standards and two decades of experience by OHCHR in advising, supporting, deploying and reviewing international commissions of inquiry and fact-finding missions. The guidance is mainly targeted at members of commissions/missions, the staff of such bodies, States, civil society organizations and United Nations departments that may be involved in advocating, mandating, establishing, supporting and resourcing such bodies. It is also directed at national human rights institutions, academic institutions and others who may be involved in these activities.