Twenty Irishmen, accused of belonging to a secret terrorist organization called the Molly Maguires, were executed in Pennsylvania in the 1870s for the murders of sixteen men. Ever since, there has been enormous disagreement over who the Molly Maguires were, what they did, and why they did it. Combining social and cultural history, Making Sense of the Molly Maguires paints a completely new portrait of the Molly Maguires and examines why people wrote and believed such curious things about them.

In the process, it vividly retells one of the classic stories of American labor and immigration.