There was a time over half a century ago when the conventional wisdom underlying American jurisprudence was that it was more important to assure that one innocent man not be found guilty of committing a crime he did not commit than that 99 guilty men go free. That high-minded notion was replaced—in practice, if not in theory—as the criminal justice process was criticized for becoming a deadly game whose priority of following fair procedures was causing intolerable rates of violent crime.

We have moved to a CSI era in law enforcement, and one important feature of science in detection is DNA. The advent of DNA testing in the late 1980s, resulting in 250 exonerations of men convicted for violent crimes—rape (68 percent), murder (9 percent), rape and murder (21 percent), and other crimes such as robbery (2 percent)—has led critics of the criminal justice system’s life-and-death adversarial method to question the reasons why innocent people were convicted of terrible crimes, often leading to prolonged sentences or death row. University of Virginia law professor Brandon L. Garrett examines these first 250 cases, and explores why these injustices occurred, in his sober and solidly researched book, Convicting the Innocent.

Using dramatic and telling case histories, Professor Garrett, once associated with the famous Innocence Project in New York City, painstakingly demonstrates the invaluable potential of DNA testing in scientifically demonstrating innocence. As is generally known, the human genome includes DNA, which is unique to each person. It shows up in saliva, hair, and skin, which creates a profile capable of identifying the individual who is its source. Handled correctly, it is surer evidence than is commonly found in criminal cases.