North Korea may be best known for its nuclear brinkmanship and isolation, but as a new volume on its activities in southern Africa shows, Pyongyang has long pursued an ambitious — and often overlooked — global agenda. In “Comrades Beyond the Cold War,” Tycho van der Hoog details the various ways in which the DPRK has engaged with anti-colonial guerilla fighters, newly established postcolonial governments and various other revolutionary upstarts over the decades.