<p>Nietzsche’s first book, The Birth of Tragedy (1872), was his attempt to revitalise modern German culture using the example of pre-Socratic Greek culture. Although widely accepted as the first stage of his philosophical development, I argue that BT is much more than that and can be used as the template for understanding Nietzsche’s later work. I find that a few of Nietzsche’s major ideas that sprouted in BT, and then permeated throughout his philosophical career characterise BT as his essential work and, as such, make it inseparable from the rest of his corpus. For example, justification of life only as an aesthetic phenomenon is a crucial idea directly associated with Nietzsche’s central teaching of life affirmation. Although there is a consensus in scholarly literature that, in his later writings, Nietzsche abandoned the need for life justification in order to affirm life, I find that illusion, which made life justification possible, remains indispensable in his later writings. In order to affirm life, as in his teaching of Amor Fati1 and Eternal Recurrence, Nietzsche had to implement artistic illusion as a necessary part of aesthetic experience. The necessity of illusion for life affirmation remained throughout, from his first book to his last.Nietzsche understood the will to power, as the central teaching in his later stage, to be overcoming resistance/suffering. Although he did not develop the idea of the will to power in BT, he has signalled it by introducing the unique type of individual as ‘nobly formed natures’ (BT, 18). They were able to suffer more profoundly than others, overcome that suffering, and use it as a platform for life justification via tragedy. Nietzsche later says (TI, XI, 5) that he has already started to affirm life in BT. His goal was not to see the tragedy as the proof of pessimism, as Schopenhauer did, or to purify oneself from the emotions of fear and pity via tragedy, as Aristotle saw it, but to justify life. That revaluation of all values, as he calls it, already started in BT by overcoming resistance/suffering and not succumbing to it. Although agreeing with Schopenhauer’s descriptive view of suffering, Nietzsche refuses to accept his evaluation of suffering and sees it not as an obstacle that must be avoided but as the necessary condition for life affirmation. Overcoming suffering, not avoiding it, as depicted in BT, requires illusion as the necessary condition for it.Contrary to Julian Young, for whom the introduction of illusion renders BT a pessimistic book, I argue that the implementation of illusion in life justification is essential for the pre-Socratic Greek culture Nietzsche is talking about. Whilst for Young, the implementation of illusion causes non-epistemically warrantied justification of life, pre-Socratic Greek culture as understood by Nietzsche did not object to such life justification. On the contrary, the illusion was a constitutive element of their culture, religion and art, in which they have found life justified. Nietzsche wanted to recreate their culture in order to divert German culture from the road to pessimism and nihilism, which he professed, would lead her to a catastrophe in the coming century.</p>