Why do we seem to be simultaneously obsessed and outraged by people who lie, invent different identities and dupe people into believing them? Tricksters and frauds have been around for ages, making up one colourful persona after the other. How can researchers deal with dishonest historical actors, for example when looking at the fairground? In this article, Hannah Welslau looks back on a research seminar with professor Tine Van Osselaer on the topic of imposters and the ambivalent sources they have left. Liars are fascinating. In the last years, famous scammers such as the fake heiress Anna…