Plautus’s Amphitruo is unique among his surviving comedies, in that it intertwines the world of the gods – traditionally a tragic realm – with the traditional urban world of comedy. The prologue Plautus wrote for the play negotiates the question with some uneasiness. He describes the generic amalgam he has produced as a tragicomedy. The term has a complicated, often twisty, subsequent history and changes its meanings period by period. Dryden was especially drawn to mixed forms and relished technical experiment. He was also a highly sophisticated theorist of dramatic form, with a particular taste for tragicomedy. In his Amphitryon he builds on the Plautine precedent, to create a masterpiece which ostentatiously combines in a single fluent dramatic experiment a number of stylistic extremes. The play is written in six extended scenes, some of which morph several times, from farce, for instance, to matrimonial trauma, and then back again. The diversity of response this invites from the audience is integral to Dryden’s idea of the form he is exploring. A world turned upside down, as this one is, will not easily conform to default concepts of generic respectability. In retrospect, we hope, the switchback nature of the ride the play takes you on will feel coherent in vision. But spectators of this brilliant play must expect to be repeatedly surprised, as the inhabitants of its fictional world also frequently are.