Terrorism has returned to the streets of Northern Ireland. In the years after the 1998 Real IRA bombing of Omagh, which killed 29 people, violent dissident Republican groups have re-emerged as a major security threat to a region that has been denied peace, stability, and prosperity for too long.

Those responsible have many names. They are breakaways, splinter factions, spoilers, and "residual" terrorists. The Real IRA, Continuity IRA, and Óglaigh na hÉireann are only some of the groups now responsible for a growing wave of bombings, shootings, threats, and intimidation across Northern Ireland. Commonly known as "the dissidents," these are the rejectionists for whom there seems to be no negotiated settlement, no peace deal, no consensus solution that will convince them to accept the will of the majority of the people on the island of Ireland.

Divided We Stand: The Strategy and Psychology of Ireland's Dissident Terrorists presents the results of meticulous research conducted by the International Center for the Study of Terrorism at the Pennsylvania State University. Since 2007, John Horgan, Director of the center, has led a research project to monitor the activities of Ireland's new terrorists. Drawing on one of the largest open-source militant databases ever assembled, Divided We Stand describes the activities, histories, motivations, psychology, and strategy of the small, dynamic, and rapidly evolving splinter groups that continue to erode peace, stability, and normalization in Northern Ireland.