This paper considers Thomas Beddoes's role in disseminating German psychological ideas in Britain. It describes the German tradition as inaugurated by Karl Philipp Moritz (1756-93) and considers the chief differences between this tradition and the English one stemming from David Hartley. It is suggested that Beddoes found strong support for his convictions about human interiority in writings by Moritz and his followers. In particular, these enabled him to think about sanity and madness as being continuous with one another (rather than as one another's negation); they helped him locate the signs of madness in ordinary childhood behaviours; they reinforced his suspicions that many so-called nervous disorders were psychically caused; and they supplied him with a conception of unconscious passion. The paper concludes by considering Beddoes's appeal to Shakespeare's plays as a source of clinical knowledge about the nature of insanity, and argues that Beddoes has been overlooked as a crucial source for nineteenth-century psychiatrist-bardologists such as J. Conolly, J. C. Bucknill and H. Maudsley.