The Grimms called them The Quiet Folk , in Maori they are Patupaiarehe , in Wales Y Tylwyth Teg : hidden people who live unseen, speak their own languages and move around like migrants, shrouded from our eyes - like those who lived in the utopian world of Plant Rhys Ddwfn off the west Welsh coast, where this book begins. In mythology, lost lands are coral castles beneath the sea, ancient forests where spirits live, and mountain swamps where trolls...