Unification or Death, popularly known as the Black Hand (Црна рука, Crna ruka), was a secret military society formed in May 1911 by officers in the Army of the Kingdom of Serbia. It gained a reputation for its alleged involvement in the assassination of Archduke Franz Ferdinand in Sarajevo in 1914 and for the earlier assassination of the Serbian royal couple in 1903, under the aegis of Captain Dragutin Dimitrijević (a.k.a. "Apis").
The society formed to unite all of the territories with a South Slavic majority that were not then ruled by either Serbia or Montenegro. It took inspiration primarily from the unification of Italy in 1859–1870, but also from the unification of Germany in 1871.