J.R.R. Tolkien’s The Silmarillion was released in 1977.
Tolkien died in 1973, leaving a large and complex body of writings about the history of his invented world. His son Christopher Tolkien edited and arranged these materials for publication, with assistance from fantasy author Guy Gavriel Kay. The resulting book was published by George Allen & Unwin on 15 September 1977.
The Silmarillion presents myths and histories from the creation of Eä through the First Age and beyond. It includes the Valaquenta, the Quenta Silmarillion, Akallabêth, and Of the Rings of Power and the Third Age. It is not a conventional sequel to The Lord of the Rings: much of it reads like a mythological or historical account, and some passages survive in multiple versions because Tolkien repeatedly revised his legendarium.