Red Book of Westmarch

The first definite mention of the Red Book is in the Prologue to The Lord of the Rings, which states that Bilbo took it with him when he left the Shire in III 3001. It was in a very unfinished state at this point; the important Translations from the Elvish would not be added until after Bilbo's arrival at Rivendell. Nevertheless, it must have predated Bilbo's departure by some time, and may even date back to his journey to Erebor sixty years before.

We know that the Red Book survived at least until IV 172, because a Gondorian scribe named Findegil completed a copy of it in that year (this is, incidentally, the last definitely dated event anywhere in Tolkien's work). It did not last indefinitely, however, as the Prologue tells us: 'The original Red Book has not been preserved, but many copies were made...'