tout est pour le mieux dans le meilleur des mondes possibles.

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The title Brave New World derives from Miranda's speech in William Shakespeare's The Tempest, Act V, Scene I.
O wonder!
How many goodly creatures are there here!
How beauteous mankind is! O brave new world,
That has such people in't.
— William Shakespeare, The Tempest, Act V, Scene I, ll. 203–206
Shakespeare's use of the phrase is intended ironically, as the speaker is failing to recognise the evil nature of the island's visitors because of her innocence. Indeed, the next speaker replies to Miranda's innocent observation with the statement "They are new to thee..."
Translations of the title often allude to similar expressions used in domestic works of literature: the French edition of the work is entitled Le Meilleur des mondes (The Best of All Worlds), an allusion to an expression used by the philosopher Gottfried Leibniz and satirised in Candide, Ou l'Optimisme by Voltaire (1759). The first Standard Chinese translation, done by novelist Lily Hsueh and Aaron Jen-wang Hsueh in 1974, is entitled "美麗新世界" (Pinyin: Měilì Xīn Shìjiè, literally "Beautiful New World").