The Book of Lost Tales
The book compiles material previously published elsewhere, namely "The Tale of The Fall of Gondolin" and "Isfin and Eöl" both published in "The Book of Lost Tales, Part Two"; "Turlin and the Exiles of Gondolin" published in "The Shaping of Middle-earth"; excerpts from the "Sketch of the Mythology" and "Quenta Noldorinwa", both published in "The Shaping of Middle-Earth"; and "Of Tuor and The Fall of Gondolin" published in "Unfinished Tales", along with excerpts from "The Silmarillion" and elsewhere.