The International Civic and Citizenship Education Study (ICCS) 2009 studied the ways in which countries prepare their young people to undertake their roles as citizens. ICCS 2009 was based on the premise that preparing students for citizenship roles involves helping them develop relevant knowledge and understanding and form positive attitudes toward being a citizen and participating in activities related to civic and citizenship education. These notions were elaborated in the ICCS 2009 framework, which was the first publication to emerge from ICCS 2009 (Schulz, Fraillon, Ainley, Losito, & Kerr, 2008). The reports of results from ICCS 2009 (Schulz, Ainley, Fraillon, Kerr & Losito, 2010a & 2010b; Kerr, Sturman, Schulz & Burge, 2010; Schulz, Ainley, Friedman & Lietz, 2011) document variations among countries in relation to a wide range of different civic-related learning outcomes, actions, and dispositions. They also describe to what extent those outcomes are related to characteristics of countries, and the associations of these outcomes with student characteristics and school contexts. ICCS 2009 considered six research questions concerned with the following: (1) Variations in civic knowledge; (2) Changes in content knowledge since 1999; (3) Students' interest in engaging in public and political life and their disposition to do so; (4) Perceptions of threats to civil society; (5) Features of education systems, schools, and classrooms related to civic and citizenship education; and (6) Aspects of students' backgrounds related to the outcomes of civic and citizenship education. ICCS 2009 gathered data from more than 140,000 Grade 8 (or equivalent) students in more than 5,300 schools from 38 countries. These student data were augmented by data from more than 62,000 teachers in those schools and by contextual data collected from school principals and the study's national research centers. ICCS 2009 was an ambitious and demanding study, involving complex procedures for assessing students' achievement, drawing student samples, and analyzing and reporting the data. In order to work effectively with the ICCS 2009 data, it is necessary to have an understanding of the characteristics of the study, which are described fully in the "ICCS 2009 Technical Report" (ED544622). It is intended, therefore, that this ICCS 2009 International Database (IDB) User Guide be used in conjunction with the ICCS 2009 Technical Report. Whereas the ICCS 2009 IDB User Guide describes the organization and content of the ICCS 2009 International Database, the "ICCS 2009 Technical Report" provides the rationale for the techniques used and for the variables created. An appendix lists organizations and individuals responsible for ICCS 2009. (Contains 14 tables, 49 figures, and 8 footnotes.) [For Supplement 1 (International Version of the ICCS 2009 Questionnaires), see ED544605. For Supplement 2 (National Adaptations of International Questionnaires), see ED544616. For Supplement 3 (Variables Derived from the Survey Data), see ED544617. For Supplement 4 (ICCS 2009 Sampling Stratification Information), see ED544624. For Supplement 5 (ICCS 2009 Released Items), see ED544619.]