This monograph examines the imperial Russian campaign to quell rebellion in the North Caucasus from 1801 to 1864 and the Bolshevik suppression of the Basmachi rebellion in Central Asia from 1919 to 1933. The Caucasian War and the Basmachi rebellion featured Muslim insurgent movements that exploited inaccessible mountain terrain and relied upon the local population for recruitment and support. The imperial Russians and Bolsheviks both struggled to adapt their civil and military operations to defeat an elusive enemy and establish control over a diverse and fractured society. The analysis tests the effectiveness of key principles found in population-centric counterinsurgency theory and doctrine in the imperial Russian and Bolshevik counterinsurgent operations. The evidence suggests that the synchronization of military and nonmilitary operations through unity of effort contributed to Russian and Bolshevik victory by isolating the insurgent forces from the local population. The analysis also identifies significant risks and costs associated with employing a population-centric approach to counterinsurgency.