First, the cover is misleading. In Spanish it says that it's for VOICE. For some unknown reason, in English someone translated it badly into HIGH VOICE. Only a few of the songs are for high voice.
Second, the book contains songs in Basque, Gallego, and Catalan. No pronunciation guide is given for these languages. No warning is given that not all songs are in Castillian Spanish.
Third, seven of the songs are written for children.
Overall, there are three songs in Castillian that are suited for high voice.