Scientific evidence is commonplace in today's criminal trials. From hair and handwriting analysis to ink and DNA fingerprints, scientists have brought their world to bear on the justice system.

Combining political analysis, scientific reasoning, and an in-depth study of specific state supreme court cases, Black Robes, White Coats is an interdisciplinary examination of the tradition of "gatekeeping," the practice of deciding the admissibility of novel scientific evidence. Rebecca Harris systematically examines judicial policymaking in three areas forensic DNA, polygraphs, and psychological...