Book excerpt: The rapid growth in popularity of computer and video games, particularly among children and teenagers, has given rise to public concern about the effects they might have on youngsters. The violent themes of many of these games, coupled with their interactive nature, have led to accusations that they may be worse than televised violence in affecting children's antisocial behaviour. Other allegations are that they have an addictive quality and that excessive playing results in a diminished social contact and poorer school performance. But how bad are video games? There are strong methodological reasons for not accepting the evidence for video games effects at face value. There are also positive signs that playing these games can enhance particular mental competencies in children. This book provides an up-to-date review and critique of research evidence from around the world in an attempt to put the issue of video game effects into perspective.