This chapter summarizes the origins and evolution of armed conflicts active in 2015, as recorded by the Uppsala Conflict Data Program (UCDP). Descriptive profiles are provided of active armed conflicts that reached the level of war either in 2015 or in one or more previous years. The UCDP defines armed conflict as a contested incompatibility that concerns control over government or territory, or both, where the use of armed force between two parties results in at least 25 battle-related deaths in a calendar year. UCDP data are compiled mainly using secondary written sources, including reports by news media as well as human rights institutions and organizations. Kurdish resentment of discriminatory policies and human rights abuses by the Turkish government led to the formation in 1974 of the Kurdistan Workers' Party (PKK), a Marxist-Leninist group aiming for an independent and socialist Kurdish state.