"I went into the field with a typically objective scientific question: What causes people to join hate groups?" writes James Aho. In the course of his wide-ranging observations, interviews, and sometimes dangerous investigations into the persistence of right-wing extremism in the Unites States, he has come to recognize a seemingly universal need of social groups to identify 'the enemy', that which is held responsible for the bad things in life.

In This Thing of Darkness Aho attempts to understand the making and breaking of domestic and foreign enemies in general. He considers enemies as social products rather than as psychological phenomena, and focuses on how enemies are perceived or constructed in the minds of a group or society at large.