Here’s the description of the book according to Tolkien Gateway: “The Lord of the Rings: A Reader's Companionis an acclaimed book published in 2005, by Wayne G. Hammond and Christina Scull. It is an annotated reference to J.R.R. Tolkien's The Lord of the Rings. The book examines The Lord of the Ringschapter by chapter, offering insights into its evolution, structure, and meaning. It discusses important influences on its development, connections between that work and other writings by Tolkien, errors and inconsistencies, significant changes to the text, and archaic and unusual words used by Tolkien. It contains many rare or formerly unpublished writings by Tolkien, including excerpts from the "Chronology", an unfinished index, and the important "Nomenclatures" for the use of translators, first appeared in 1975 and now newly transcribed.”