Chapter 12, ‘Deception, self-deception, and the transformative actor’, returns to the argument with which the book started: the qualitative difference between the actor-in-action and actor-in-character. The chapter looks at acting from the ethological perspective of Deception Theory (Robert Trivers): the proposition that most primates, humans included, have developed sophisticated mechanisms to believe in fictional realities (deceive themselves) in order better to deceive others and, thus, gain advantages within the social group. Other members of the group, however, develop equally sophisticated methods of detecting the deception and society has evolved cultural ways for practising these essential social skills. From this perspective, watching an actor at work may be understood as a sophisticated form of practising deception; transformative acting offers particularly high levels of deception, necessitating equally high levels of detection. The chapter concludes the book by stating that, in professional contexts, transformative acting is a matter of degree, that it is not always appropriate, but that when it is appropriate it offers actor and spectator alike a higher level of aesthetic experience precisely because it involves higher levels of deception.