Which Tolkien work contains the creation myth of Arda, beginning with the Ainulindalë?

The Silmarillion contains the creation myth of Arda, beginning with the Ainulindalë.

The Silmarillion is a posthumously edited collection of Tolkien’s mythological and historical writings. Its opening section, Ainulindalë, describes how Eru Ilúvatar creates the Ainur and how their music becomes the foundation of the world. The work then moves through the shaping of Arda, the history of the Elves, and the major conflicts of the First Age.

Christopher Tolkien edited the book for publication after his father’s death, and it appeared in 1977. It is not a conventional novel with one continuous protagonist. Readers sometimes confuse it with The Book of Lost Tales, an earlier form of Tolkien’s legendarium that was later published in edited volumes of The History of Middle-earth.