* AccidentallyCorrectWriting: Tolkien seems to have acquired the gift of prophecy whilst writing ''The Notion Club Papers'' in 1944, given that he gives 1987 as the date of [[http://en.wikipedia.org/wiki/Great_Storm_of_1987 the greatest storm ever to hit England]].
* NamesTheSame: Tolkien changed names of characters and locations at least once with every draft or linguistic revision, and also recycled old ones. Names that would later be applied to well-known characters in ''The Lord of the Rings'' show up many years before that book was conceived, attached to completely unrelated characters.
** For example, one Gimli first appears in the "Tale of Tinuviel" (written in 1918-1920) as a "Gnome"[[note]]which, strangely enough, at this stage was a synonym for Noldorin Elf[[/note]] and fellow prisoner of Beren in Tevildo's kitchens.
** Legolas Greenleaf was first the name of an elf leading the fleeing people of Gondolin over the plains of Tumladen and over the pass of the Cirith Thoronarth.
** Even within the ''Silmarillion'' part of the legendarium, names sometimes switch places bizarrely. For a short time Beren was named Maglor.
* ScienceMarchesOn: Tolkien firmly believed that space travel was physically impossible; in ''The Notion Club Papers'', which takes place in 1987, it still hasn't been accomplished. About a decade later, Sputnik would prove him wrong.
* WhatCouldHaveBeen: The point of the ''History''.
* WriteWhatYouKnow: "The Fall of Gondolin" from ''The Book of Lost Tales'' part 2 is clearly inspired by Tolkien's then-recent experiences in UsefulNotes/WorldWarI, down to Morgoth's mechanical dragons evoking the early tanks used in the war.
* WriteWhoYouKnow: "The Notion Club Papers" is an AffectionateParody of Tolkien's own experiences with the Inklings--in particular, Michael Ramer resembles Creator/CSLewis and Alwin Arundel Lowdham resembles Tolkien himself. Also, [[AuthorAvatar Author Avatars]] Alwin Arundel Lowdham from that story and Alboin Erroll from ''The Lost Road'' are both linguists.