: This is the final, posthumously published volume of the classic Arthurian series The Once and Future King . It serves as a philosophical conclusion where Merlyn reappears to King Arthur before his final battle to discuss ethics, politics, and the causes of war.

: The first in a trilogy that treats Merlin’s powers as a blend of keen observation and reason rather than just pure magic.

: This is a non-fiction exploration that examines the historical and mythological incarnations of Merlin throughout history from various cultural perspectives. Other Significant Retellings

If you are looking for Merlin's story more generally, these "classics" are frequently cited by reviewers on Reddit and Goodreads :

: Subtitled "The First Book of Merlin," this 1988 historical fantasy draws heavily from original Celtic and Germanic myths to create a more grounded, scholarly version of the enchanter.

The phrase "Book of Merlin" can refer to several different literary works, ranging from classic Arthurian retellings to modern fantasy novels.