Coming from the darker side of J.R.R. Tolkien's imagination, "The Lay of Aotrou and Itroun" is an important non Middle-earth work to set alongside his other retellings of existing myth and legend, The Legend of Sigurd and Gudrún, The Fall of Arthur and The Story of Kullervo. Together with Tolkien’s “Corrigan Poems”, which are included in this book, the Aotrou and Itroun texts comprise a sequence that was the outcome of a comparatively short but intense period in Tolkien's life when he was deeply engaged with Celtic languages and mythologies.