This book provides a new approach to explaining prolonged rebellions and insurgent wars, as well as a more nuanced and multi-faceted account of the entire lifespans of rebel and insurgent groups. Since 1945, rebel and insurgent groups have increasingly dragged larger, better funded, and ostensibly militarily superior regimes into protracted intrastate conflicts. This book demonstrates how they were able to endure the hardships of warfare thanks to decisions made before the conflict erupted––a period of time the author refers to as “incubation.” Using case studies on Latin American insurgencies, the author demonstrates that their capacity to endure was directly associated with both the length and quality of each group’s prewar preparations.