The book's publication followed Stanford's work editing three volumes on the collection made by George Petrie of the folk music of Ireland and he was supported in this by Arthur Somervell (his ex-pupil and Inspector of Music at the Board of Education).
The aim of the work was to provide older school children with a "gateway to musical taste and knowledge".
It argues these are "merely intended to suggest sufficient harmony to make clear the tonality of each song, and in some cases to reinforce the characteristic rhythm, without distracting the attention of the singers from the melody itself".
The book also notes the likelihood that English children, whilst they might find the Celtic scales and intervals difficult at first the "trouble involved will be amply repaid by the widening of their musical horizon, and by the more deeply poetical influence which Keltic music will exert upon the young mind".
[1][2][3] Cox (1992) argues in a polemical historiography of the book that "The National Song Book proclaimed the hegemony of the literate tradition as opposed to the oral, and considers the view that national songs contained within them the danger of the manipulation of patriotism.