Judge Learned Hand called “the ghost of the innocent man convicted” an “unreal dream.” But in “Convicting the Innocent,” Brandon L. Garrett shows that it can be a “nightmarish reality.” Since the late 1980s, DNA testing has exonerated more than 250 wrongly convicted people, who spent an average of 13 years in prison for crimes they didn’t commit. (There is every reason to think that more people have been wrongly convicted since then, but only these 250 have been definitively exonerated by postconviction DNA tests.) Seventeen of the 250 were sentenced to die, and 80 to spend the rest of their lives in prison. By poring over trial transcripts and interviewing lawyers, prosecutors and court reporters, Garrett, a law professor at the University of Virginia School of Law, seeks to explore who these 250 innocent people are, and why they were wrongly convicted. His alarming conclusion: the wrongful convictions were not idiosyncratic but resulted from a series of flawed practices that the courts rely on every day, namely, false and coerced confessions, questionable eyewitness procedures, invalid forensic testimony and corrupt statements by jailhouse informers. Garrett’s book is a gripping contribution to the literature of injustice, along with a galvanizing call for reform.