The Grimms called them The Quiet Folk, in Māori 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 lurk. Strip away the mythology, and they become valleys and villages flooded to provide drinking water to neighbouring kingdoms, campsites where travellers are told they can't travel, and reservations where the rights of first nations people are ignored. The folk tales in this book tell of these lost lands and hidden people, remembered through migrations, dreams and memories.