[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/81udl9q3fvl.jpg]]

->'''"So my Table was not a failure — Master?"''
->''"Certainly not. It was an experiment. Experiments lead to new ones"''

''The Book of Merlyn: The Unpublished Conclusion to The Once and Future King'' is the posthumously published fifth book in [[Creator/THWhite T.H. White's]] retelling of Myth/ArthurianLegend. Written in the 1940s, it remained unpublished due to wartime paper shortage and its anti-war message. It would not be included in the 1958 composite edition of ''Literature/TheOnceAndFutureKing''.

White's manuscript was finally published in 1977, thirteen years after his death. It was published as it was written with no editing done to bring it more in line with the omnibus version of "The Once and Future'', so it reflects the installments of the tetralogy as the individual books they were originally published as before they were revised to be collected in one volume.

Chronologically, it is set ''within'' the fourth book, during the last few pages. On the eve of the FinalBattle between Myth/KingArthur and Mordred, Arthur is once more taken by Merlyn to contemplate various things. Together they arrive at the Badger's Sett Arthur visited in his childhood where he is reunited with his animal mentors from his youth. Together they discuss the evils of humanity, war, and what can be done to cure it. Through it all, Arthur, thoroughly worn out and exhausted after seeing his noble dream shattered, is unsure if he even ''wants'' to face his bastard son in battle.

Notable in the book are two episodes where Arthur is once again turned into animals: first an ant and later a goose. These episodes would be recycled into "The Sword in the Stone" when it became part of "The Once and Future King", since White's publisher would not allow the fifth volume to be in the collected book, despite White's wishes.
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!!This work provides examples of:
* AntWar: The Author envisioned this here, but ExecutiveMeddling put it in ''The Sword in the Stone''.
* AuthorTract: The whole damn book is one on White's opinions of human nature, whether or not it is good by nature, the origins of war and plenty more. As Sylvia Townsend Warner says in the introduction:
--> "Merlyn the main speaker, is made a mouthpiece for spleen, and the spleen is White's. His fear of the human race, which he seemed to have got the better of, had recurred, and was intensified into fury, fury against the human race, who make war and glorify it."
* BackForTheFinale: Merlyn and all of Arthur's animal mentors from "The Sword in the Stone" show up to give him one final piece of advice.
* FaceDeathWithDignity: Arthur's death -- to the very last, fighting to stem the tide of war and bring peace.
* FinalBattle: The evening before it.
* GenreShift: "The Once and Future King" was unashamedly HighFantasy. "The Book of Merlyn" is more of an academic debate on the nature of human morality.
* HopeSpot: Before the final battle, Arthur offers a truce with Morded. He'll give him half of his kingdom to avoid war. Mordred agrees as it seems peace will happen... but as the treaty is being signed, one of Mordred's soldiers draws his sword to kill a snake. Arthur's army sees this an act of treachery, and the battle begins in earnest.
* HumansAreTheRealMonsters: A main point put forward by many of the animals. They even go so far to suggest Homo Ferox [[note]]wild man[[/note]] is a far more scientific designation for humanity than Homo Sapiens [[note]]wise man[[/note]].
* RememberTheNewGuy: Subverted. Amongst Arthur's animal mentors are Goat and Snake, whom weren't seen in "The Once and Future King", but who were part of the ''original'' version of "The Sword in the Stone".
* StrawmanPolitical: InUniverse, the Badger is suddenly one championing Communism. Merlyn and the other find it exasperating.
* YankTheDogsChain: Arthur's tranquil experiences as a goose, and his incipient romance with Lyo-lok, lead him quite prepared to forget Camelot and just stay there. Merlyn's timing for yanking him back to humanity is just cruel.
* WhatTheHellHero: After the goose episode, the animals are completely unaware of Arthur's unhappiness and total emotion exhaustion (save the Goat). It's the Hedgehog of all animals who gives the others, even Merlyn, a much needed dressing down.
* WhereAreTheyNowEpilogue: The last chapter details the fate of the surviving characters:
** Guenever enters a convent and eventually becomes an abbess.
** Lancelot and seven of his retainers become hermits in a monastery. Lance's last miracle is making the room he died in smell like Heaven.
** The remaining Knights of the Round Table, Ector, Bor, Demaris, and Bleoberis make a pilgrimage to the Holy Land and die on Good Friday.
** The fate of King Arthur's remains is discussed. Their fate is a mystery. One theory is that Henry II removed his remains at Glastonbury to quell Welsh nationalism.
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