Which Tolkien book contains the creation story of Arda called the Ainulindalë?

The Silmarillion contains the creation story of Arda called the Ainulindalë. Its title is commonly translated as “The Music of the Ainur.”

In the Ainulindalë, Eru Ilúvatar teaches the Ainur a great musical theme. Their music helps bring the world into being, while the rebellious Melkor introduces discord. The account establishes the theological and cosmological foundation for Tolkien’s mythology before the later histories of the Elves, Men, and other peoples.

The Silmarillion begins with this creation account and then moves through several connected sections, including the Valaquenta, the Quenta Silmarillion, and material about the Second and Third Ages. The Ainulindalë is therefore not a chapter of The Lord of the Rings or The Hobbit, though its ideas underpin the history of both works.