The Seal Children by Jackie Morris
When a fisherman called Huw falls in love with a selkie - half-woman, half-seal - she gives him her sealskin as a sign of her love, and bears him two children, Ffion and Morlo, before returning to her own people. A few years later a stranger comes to the village, telling of a land far away, and Ffion and Morlo remember their mother's stories of the cities of gold and pearls beneath the waves...This is a beautiful, atmospheric story of love and freedom, and the first picture book written and illustrated by Jackie Morris.