The book was written by several authors, chiefly by Bilbo Baggins and his nephew Frodo Baggins, the Ringbearer, though contributions were also made by Thain Peregrin Took, Meriadoc Brandybuck, Mayor Samwise Gamgee and King Elessar of Gondor.
It was the subject of translations and transcriptions over several generations.
The first Red Book was written as a diary by the Bilbo Baggins and recounted his quest for Erebor, which he called There and Back Again. He filled it with Elven lore when he retired to Rivendell in a section called Translations from the Elvish. Frodo later organized Bilbo's manuscript and used the Red Book to write down the tale of his own quest during the War of the Ring.
Apart from Bilbo's translations of Elven legends from the Elder Days, there were various Hobbit poems and a much background information on the realms of Arnor, Gondor and Rohan, added to it by Peregrin Took and Meriadoc Brandybuck from their contacts in Rohan and Gondor. Other material was provided by King Elessar of Gondor.
After Bilbo and Frodo left on a final journey to the West, the Red Book passed into the keeping of Samwise Gamgee, mayor of the Shire. The book was left in the possession of Sam Gamgee's eldest daughter, Elanor Fairbairns, and her descendants (the Fairbairns of the Towers or Warden of Westmarch).
The original book was kept in a red case (with a three-volume Elvish Translation and a fifth volume genealogical tables and commentaries). Several copies, with various notes and later additions, were made and copies were passed on to future generations, of which one, the "Thain's Book", is the most important.
The "Thain's Book" was a copy of the Red Book of Westmarch made as ordered by King Elessar. It was brought to him in Gondor by Thain Peregrin Took. In Gondor, it was annotated and expanded and a copy of it was made by Findegil, the King's Writer, in Fo.A. 172. This copy was returned to the head of the Took family, the Thain of the Shire, at Great Smials.
The original version of the Red Book contained the false story of Bilbo's journey to Erebor in which Gollum willingly gave the One Ring to Bilbo, and there was no trace of the Ring's hold over Gollum. Later copies of the Red Book contained the true account, written in by Frodo, which states that Bilbo came across the Ring by accident.
Gandalf the Istari also held that had he authored There And Back Again, the contents would have been quite different, as Bilbo omitted (or failed to notice) the ill humour with which the Dwarves of Thorin Oakenshield's company bore his presence. It should be noted that There And Back Again recounts the Quest of Erebor only as its author saw it.
- ↑ J.R.R Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "The Quest of Erebor", p. 418