End of Its Rope: How Killing the Death Penalty Can Revive Criminal Justice. By Brandon L. Garrett. Cambridge, Mass.: Harvard University Press. 2017. Pp. 331. $29.95. Capital punishment in America is facing its own slow but assured death. Jurors nationwide are increasingly reluctant to impose the death penalty, even in states where capital punishment is still on the books. In End of Its Rope, Professor Brandon L. Garrett embarks on an epic game of “whodunit?,” using hand-collected data and case studies to identify the factors contributing to the death penalty’s demise. For Henry McCollum, an increased awareness that wrongful convictions for capital offenses commonly occur led to exoneration (pp. 18–48). For James Holmes (p. 55) and Samuel Cooper (pp. 59–60), appeals to mercy and evidence of the past abuse they suffered helped them avoid capital punishment. Garrett explores how protection for the mentally ill and disabled (p. 65), improved defense lawyering (p. 130), and the availability of life without parole (LWOP) (p. 167) also shift preferences away from the death penalty. End of Its Rope is an exercise in hopeful realism: although systemic failures such as mandatory sentencing, racial bias, and overuse of LWOP still persist (pp. 167–86), Garrett derives from the death penalty’s swan song lessons of justice and mercy needed to fix our criminal justice system.