Terrorism expert Rohan Gunaratna. His new book is Inside Al Qaeda: Global Network of Terror. Gunaratna spent five years conducting interviews with al Qaeda members, doing field research and monitoring the group's infiltration in communities in North America and Europe. He is the author of six books on armed conflict and a research fellow at the Centre for the Study of Terrorism and Political Violence, University of St. Andrews, Scotland. He's lectured worldwide on terrorism and served as consultant to many governments.