By Tolkien scholars
Douglas Kane writes in Journal of Tolkien Research that The Fall of Gondolin was the first of Tolkien's three "Great Tales" to be written, and the last to be published, the other two being the Great Tale of Túrin Turambar (published in The Children of Húrin, 2007, edited into a continuous story) and Beren and Lúthien (2017, presented as a set of versions of the story). That left the tale which was "arguably the one in which the world of Middle-earth is most vividly presented and in which Tolkien’s philosophical themes are most profoundly expressed."[9] Kane adds that although the book collects material already published, "it still succeeds in rounding out that task", for instance by putting the "Sketch of the Mythology" in the prologue. He wonders, though, why the editor included part of the poem "The Flight of the Noldoli from Valinor" (already in The Lays of Beleriand), but omits the poem fragment "The Lay of the Fall of Gondolin" which is far more obviously relevant. Kane admires Alan Lee's illustrations, both in colour and in black and white, as providing "a perfect complement" to the final book in the "unique and remarkable" collaboration between Christopher Tolkien and his father.[9]
Jennifer Rogers, reviewing the book for Tolkien Studies, writes that it "highlights the power of the Gondolin story in its own right with minimal editorial intrusion."[10] As Tolkien's first tale and the last one to be published by his son, the book is "laden with the sense of weight such a publication brings", taking the reader back to the place where the whole Legendarium began, the story about Eärendel (later called Eärendil).[10]