This chapter gives an overview of the multi-faceted life of Thomas Harris and its cultural importance. Harris was the owner and manager of Covent Garden theatre for nearly five decades, a confidant of George III, a Secret Service agent, a notable philanthropist, and a bagnio owner in the underworld of Covent Garden. As a result, this chapter introduces a number of clandestine worlds, including the Secret Service where ministers waited for the stirrings of revolution upon London’s streets. This section is driven by three considerations: why Harris has disappeared from history, the many difficulties for the researcher writing his biography, and the ways of understanding his character. In anticipating what is to come, this part also introduces the relationships, both familial and professional, that Harris nurtured — along with the characters involved in the main events of his life including Richard Brinsley Sheridan and George Rose.