This compendium summarises questionnaires completed by different agencies as part of an OECD DAC mapping exercise of early warning and early response systems (December 2007 to May 2008). Where relevant, it also draws on information from other reviews of early warning systems (e.g. Cilliers, 2005; Lavoix, 2007), as well as other institutional documents available from respondents. The compendium does not include details of early warning systems/response mechanisms and instruments where respondents were unable to complete questionnaires. It serves as a supplement to the present OECD/DAC report Preventing Violence, War and State Collapse: The Future of Conflict Early Warning and Response. The compendium is organised into governmental, inter-governmental and nongovernmental early warning systems and response mechanisms/instruments. The different warning systems and response mechanism/instruments covered are described in brief profiles.