This book argues that Nietzsche bases his affirmative morality on the model of individual responsiveness to otherness which he takes from the mythology of Dionysus. The subject is not free to choose to avoid such responding to the demands of the other. Nietzsche finds that the basic mode of responding is pleasure. This feeling, as a basis for morality, underlies the morality which is true to the earth and the major concepts of "will to power", "eternal return", and "amor fati". The priority of otherness makes all thought ethical and not only aesthetic. The basis of all meanings combines the fundamental impulse of responding outwards with an immediate complement in the individual interpretation-world. This is specifically ethical because the recognition of our own historical specificity arises as a result of the refusal of others to become mere differences within our notion of the Same, and through their demand that we "become who we are" in the recognition of their separate existence.

Nietzsche and the Dionysian argues that the shuddering mania of the affect associated with Dionysus in Nietzsche's early work runs as a thread through his thought and is linked to an originary interruption of self-consciousness articulated by the philosophical companion. In this capacity, the companion can be considered a 'mask of Dionysus', or one who assumes the singular role of the transmitter of the most valuable affirmative affect and initiates a compulsion to respond which incorporates the otherness of the companion. In the context of such engagements, Nietzsche envisages 'Dionysian' or divine 'madness' within an optics of life, through which an affirmative ethics can be thought. The ethical response to the philosophical companion requires an affirmation of the plurality of life, formulated in the imperatives to be 'true to the earth' and 'become who you are'. Such an ethics, compelled by the Dionysian affect, grounds any future for humanity in the affirmation of the earth and life.