SS Libau was a merchant steam ship. In 1916 she was disguised with the identity of a Norwegian vessel named the SS Aud in an attempt to carry arms from Germany to Ireland as part of the preparation for the Easter Rising.

Arms trafficking or gunrunning is the illicit trade of contraband small arms, explosives, and ammunition, which constitutes part of a broad range of illegal activities often associated with transnational criminal organizations. The illegal trade of small arms, unlike other organized crime commodities, is more closely associated with exercising power in communities instead of achieving economic gain. Scholars estimate illegal arms transactions amount to over US$1 billion annually.