Which Tolkien work contains the creation story of Arda and the history of the Silmarils?

The Silmarillion contains the creation story of Arda and the history of the Silmarils.

The book opens with the Ainulindalë, a creation account in which the supreme being Eru Ilúvatar brings the world’s great musical vision into being. Its next major section, the Valaquenta, describes the Valar and Maiar, while the Quenta Silmarillion recounts the wars surrounding the three jewels made by Fëanor.

The Silmarils contain the light of the Two Trees of Valinor. Their theft by Morgoth drives much of the First Age’s tragedy, including the exile of the Noldor and the long wars against Morgoth in Middle-earth.

Tolkien did not publish the completed book during his lifetime. His son Christopher Tolkien edited material from the author’s manuscripts, and The Silmarillion appeared in 1977, four years after Tolkien’s death. The Children of Húrin is a separate edited publication focused on one First Age story.