The pervasiveness of surveillance, punishment, and control within and outside of spaces such as jails, prisons, and detention centres suggests that the carceral is becoming an increasingly prevalent presence in our lives, going beyond historical standards. The contemporary use of electronic monitoring extends carceral territory beyond prison walls, into people's homes and everyday lives.Empirically and empathetically driven, Portable Prisons is a telling exploration of the electronic monitoring of offenders based on an ethnographic case study from Scotland. Electronic monitoring must be understood - in both intent and effect - as a carceral practice, an expression of the carceral state and its overreaching punitive capabilities. James Gacek demonstrates that various people experience punishment by means of restrictions around mobility, space, and time in ways that strongly overlap with the reported experiences of interviewed prisoners. Drawing attention to how the neoliberal state outsources the labour of punishment to private corporations and the punished themselves, he also rejects the idea that "soft" punishment is in any way related to the movement for decarceration.Offering an original contribution to our understanding of the geography of incarceration, Portable Prisons is a sophisticated account of electronic monitoring, underlining the growing significance of this field.