This project seeks to understand why post-war armed organizations endure, go out of business or shift to a new sector (legal politics, crime) and why ex-combatants either return to violence or successfully reintegrate into civilian life. To explain this variation, Political Science offers macro-level theories and micro-level empirics, but nothing in between. A major advance in the study of conflict and peace would come from filling this gap and theory-building at the organizational level. Through in-depth analysis of demilitarization processes in Colombia, this study aims to develop a theory of the post-war insurgent firm and its ex-combatant employees. It proposes that an individual’s likelihood of reintegration depends not on the variables identified by pre-war recruitment theory, but on the individual's relationship to ex-combatant networks and the post-conflict trajectory of his/her armed group. This trajectory, in turn, is hypothesized to be a function of the armed organization’s endowment, adaptability and preferences. The project will employ a multi-method approach. First, it will conduct in-depth interviews with experts on each Colombian rebel and paramilitary organization. Second, it will field an individual-level survey of 1000 ex-combatants and civilians and third, it will realize ethnographic case studies in Bogotá and Medellín. The study’s organizational focus solves several weaknesses in the macro literature, namely the assumption of semblance between pre- and post-war peace and the methodology of testing sub-national dynamics with country-level data. The organizational focus also solves problems in the micro literature, specifically its treatment of ex-combatants as independent agents, rather than as embedded in a dense web of ex-insurgents and armed institutions which structure their decisions to demobilize and reintegrate.