Introduction societies into account. Accordingly, the reference guide provides insight into OSCE activities with regard to institution building, community security, education, electoral reform, reconciliation, diversity, and people-to-people contacts. The reference guide also contributes to strengthening the OSCE’s institutional memory and enhancing the organization’s capacity for building peace in a sustainable and holistic manner. In seeking synergies and strengthening its co-operation with other actors, the OSCE has been working with all relevant stakeholders, including governments, political parties, civil society, other international organizations and agencies, non-majority communities, national minorities, and local citizenry. The OSCE has ensured the participation of women and youth1 throughout its activities and encouraged the inclusion of vulnerable groups in all processes. The guide sets out the concept of building sustainable peace, the OSCE’s comprehensive approach and instruments, and some of the challenges that had to be overcome in building sustainable peace and supporting democratic transitions in South-Eastern Europe. The OSCE’s comprehensive approach is then illustrated through thematically-clustered examples that highlight the OSCE’s work. It is hoped that this guide will be a useful resource for all who want to benefit from the OSCE’s experiences in this important area. 1  In the absence of an OSCE-wide definition of youth, this reference guide follows UN Security Council resolution 2250 (2015) on Youth, Peace and Security, which defines youth as “persons of the age 18-29 years old”. However, for the purpose of this guide, the term youth/young people should be understood as including people under the age of 18 years, especially in the context of education-related programmes. 11