Preventing Youth Violence: A Guide for Parents, Teachers, and Counselors was issued 20 years ago, and it had a positive impact. Yet sadly, youth violence continues at an alarming rate. This updated version, now called Preventing Youth Violence Before It Begins, reflects clinical and neuroscience advances in understanding more fully why some youth become more violent and how to improve treatment. There are four new areas of development that were not included in the original book: (1) the impact of maternal stress on the embryo, (2) significant advances in understanding the adolescent brain, (3) the development of the Adverse Childhood Events Scale (ACE), and (4) the important role of toxic stress. Dr. Flannery, an authority on posttraumatic stress disorder and violence, writes in an accessible, jargon-free style in order to enhance our understanding of troublesome social trends.