Letter 131 is a letter written by J.R.R. Tolkien and published in The Letters of J.R.R. Tolkien.
It summarizes the Silmarillion, Hobbit and Lord of the Rings and was sent to publisher Milton Waldman. Letter 131 is included at the beginning of "The Silmarillion", except for the first edition.
Here is the link to J.R.R. Tolkien's Letter 131.
https://drive.google.com/file/d/1mE0IkYFu_Dvzw_KzJ4NNPbitTCLb1twe/view