For most of his 24 years, James Holmes seemed to be doing everything right. He worked for a summer as a counselor at a camp for needy kids, guiding them through activities designed to teach empathy, compassion and good citizenship. Another summer, he snagged a prestigious internship at the Salk Institute for Biological Studies. He attended church with his family in their quiet, upper-middle-class San Diego neighborhood, listening to his sister play bass in the worship band. He breezed through high school and college, taking a strong interest in science and graduating with honors from the University of California, Riverside....