Drawing upon both ethnographic research and genealogical analysis, this book represents the first in-depth scientific analysis of criminal offenders’ electronic monitoring (EM) in Latin America’s largest country. It focuses on three empirical axes: 1) the implementation of EM policies against the backdrop of Brazil’s collapsing carceral system; 2) the discourses and rationalities which undergird the deployment of EM; and 3) the effects of EM upon convicts moving back and forth between penal institutions and urban spaces governed by armed militias, criminal gangs, and abusive police forces.