''The Book of Merlyn'' is the posthumously published fifth book in T. H. White's retelling of ArthurianLegend. Written in the 1940s, it remained unpublished due to wartime paper shortage and was not included in the 1958 composite edition of ''Literature/TheOnceAndFutureKing''. The manuscript was finally published in 1977.

Chronologically, it is set ''within'' the fourth book: On the eve of the FinalBattle between KingArthur and Mordred, King Arthur is once more taken by Merlyn to contemplate various things.
!!This work provides examples of:

* AntWar: The Author envisioned this here, but ExecutiveMeddling put it in ''The Sword in the Stone''.
* AuthorTract: On human nature, whether or not it is good by nature, the origins of war and plenty more.
* [[spoiler: FaceDeathWithDignity: Arthur's death -- to the very last, fighting to stem the tide of war and bring peace.]]
* FinalBattle: The evening before it.
* [[spoiler: HopeSpot: Arthur's tranquil experiences as a goose, and his incipient romance with Lyo-lok. Merlyn's timing for yanking him back to humanity is almost cruel.]]
* HumansAreTheRealMonsters: A main point put forward by many of the animals. They even go so far to suggest Homo Sapiens had a more fitting name as Homo Ferox.