This work is our fifth Small Wars Journal—El Centro anthology, covering writings first published in 2015. The themes of this anthology are focused on narcoterrorism—that is, terrorist acts carried out to further illicit narcotics trafficking pursuits--as well as impunity—which refers to the fact that gangs and cartels can carry out torture killings and other terrorist acts with little fear of governmental prosecution. The cover image of the Cártel de Jalisco Nueva Generación (CJNG) gunmen highlights the rise of a powerful new Mexican cartel which embodies this anthology's themes. – Dave Dilegge, SWJ Editor-in-Chief