The Silmarillion is a collection of myths and stories in varying styles by the writer J.R.R. Tolkien.
It was edited and published posthumously by his son Christopher Tolkien in 1977, assisted by the fantasy author Guy Gavriel Kay.
The Silmarillion has five parts. The first, Ainulindalë, tells in mythic style of the creation of Eä, the "world that is." The second part, Valaquenta, gives a description of the Valar and Maiar, supernatural powers of Eä. The next section, Quenta Silmarillion, which forms the bulk of the collection, chronicles the history of the events before and during the First Age, including the wars over three jewels, the Silmarils, that gave the book its title. The fourth part, Akallabêth, relates the history of the Downfall of Númenor and its people, which takes place in the Second Age. The final part, Of the Rings of Power and the Third Age, is a brief summary of the events of The Lord of the Rings and those that led to them.
Basically this is the book Amazon based their Rings of Power show on, but they didn't actually have the rights to the book which is why the show wasn't very cannon.
The best historical price was $11.03 over a year ago.