Unfinished Tales
Throughout his commentaries in "Unfinished Tales" and the twelve volumes of "The History of Middle-earth", Christopher Tolkien points out differences between various versions of the original texts and the final editorial selections and occasional alterations in "The Silmarillion". In the Introduction of "Unfinished Tales" he observes that such selection was necessary to publishing a unified narrative; but in some cases he later came to feel that he went too far, for example in the ruin of Doriath: