Conspiracy theories propose that certain significant world events are caused by the secret and deliberate actions of powerful malevolent groups. This seminar will discuss the structure of conspiracy theories, how we tell them apart from real conspiracies, which also exist, and the psychological and social mechanisms and processes that give rise to them. We will address questions concerning what kinds of people and groups might be more likely to be drawn into conspiratorial thinking, how conspiracy theories spread across populations, and what their consequences are. We will also address what possible antidotes or remedies might exist or be developed in response to this kind of thinking.