Which Tolkien book contains the creation account known as the Ainulindalë?

The Tolkien book containing the creation account known as the Ainulindalë is The Silmarillion. The title is Quenya and is commonly translated as “The History of the Silmarils.”

Ainulindalë is the first section of The Silmarillion. It describes Eru Ilúvatar creating the Ainur and showing them a great musical vision. The account then explains how some of the Ainur enter the created world, called Arda, where the history of Middle-earth unfolds.

The Silmarillion was published posthumously in 1977, edited by Tolkien’s son Christopher Tolkien. It is not a conventional single narrative like The Hobbit or The Lord of the Rings; instead, it combines mythic accounts, histories, genealogies, and linguistic material. Its major stories include the creation of the world, the wars against Morgoth, the history of the Silmarils, and the downfall of Númenor.