This highly original study brings together the disparate histories of murder and enlightenment, prostitution and the cult of nature, sodomy and sentimentalism in order to retell the story of the making of the modern self. It suggests that the history of the self needs to attend more to its class dimensions, and puts this insight into practice by examining the influence of the criminal courts in spreading and negotiating changing ideas of the self. Using criminal interrogations and witness statements, Trials of the self shows that an increasing stress on psychological depth in the late-eighteenth and early nineteenth centuries was not only important for elites, but also for common and illiterate people - sometimes even more so.