Schenwar looks at how incarceration breaks the bonds that hold people together and deprives incarcerated people of exactly the kind of support and life skills necessary to reintegrate into society - which is why more than two-thirds of prisoners are re-arrested within three years of release. She draws heavily on her personal experience (her sister has spent the better part of ten years entangled in the system), as well as the struggles of other prisoners and their families.

Far from advocating the complete abolition of prisons, Schenwar simply argues that they shouldn't be the only approach. She describes how highly effective alternative justice programs in the US and other countries do a better job of both preventing recidivism and providing meaningful restitution to victims. Above all, however, Schenwar seeks to convince her readers that prisoners, for all their hurtful deeds, shouldn't be treated as "non-persons." Her book is a passionate argument that "throwing away the key" ultimately hurts individuals and society.