[1] Scholars including Gergely Nagy and Vincent Ferré have commented that Tolkien had always wanted to create a mythology, but believed that such a thing should have passed through many hands and be framed by annotations and edits of different kinds.

[2][3] This was not published in his lifetime; he left a large mass of unsorted manuscripts for his literary executor, his son, Christopher Tolkien, to work on.

His reasons for this were that it had not been intended to form part of the mythology, was a children's story, and had originally not been set in Middle-earth; it was revised during the writing of The Lord of the Rings.

[11] Liz Milner, for A Green Man Review, writes that the series provides "an unprecedented opportunity to examine a great writer's creative development over a period of 60 years".

[12] Wayne G. Hammond and Christina Scull, in VII, describe Tolkien's mythology as documented in the History as "a work of extraordinary power and scope".

Accordingly, Christopher set to work on the History to try to tackle the "infinite variety" of his father's writings, from prose to alliterative verse, from cosmology and annals to time-travel stories.

Hammond and Scull note that some readers felt that the History "should never have been published, that it is a disservice to Tolkien to display his missteps and false starts".

Hammond and Scull answer that the History was meant to present "not a fixed design, but a living creation, and the process by which Tolkien gave it life."

Now published as the twelve-volume series, The History of Middle-earth, this work presents Tolkien's mythology in its entirety, tracing the path of a remarkable vision, a musical score, if you will, from its earliest conception to its author's last meditations on his creation.

[17][18] The scholar Gergely Nagy observes that Tolkien "thought of his works as texts within the fictional world" (his emphasis), and that the overlapping of different and sometimes contradictory accounts was central to his desired effect.

Tolkien's Middle-earth writings had become, in reality and no longer only in fiction, a complex work by different hands edited, annotated, and commented upon over a long period.

"[20] Flieger comments that Christopher's remark in the introduction to The Book of Lost Tales 1, that he had made an error in not providing any sort of frame story for his 1977 The Silmarillion, is at least partly correct.

In her view, the one-volume Silmarillion "gives a misleading impression of coherence and finality, as if it were a definitive, canonical text", while in fact the legendarium from which it is adapted "is a jumble of overlapping and often competing stories, annals, and lexicons.

"[21] Vincent Ferré writes that Christopher Tolkien's editing of the 12 volumes of The History of Middle-earth, using his skill as a philologist, created an editorial frame for his father's legendarium, and for the books derived from it.

Shea states that "Experts in source-criticism now know that The Lord of the Rings is a redaction of sources ranging from The Red Book of Westmarch (W) to Elvish Chronicles (E) to Gondorian records (G) to orally transmitted tales of the Rohirrim (R)," each with "their own agendas", like "the 'Tolkien' (T) and 'Peter Jackson' (PJ) redactors".