City of Illusions (Hainish Series)

He is a full-grown man, alone in dense forest, with no trail to show where he has come from and no memory to tell who or what he is. His eyes are not the eyes of a human. The forest people take him in and raise him almost as a child, teaching him to speak, training him in forest lore, giving him all the knowledge they have. But they could not solve the riddle of his past, and at last he has to set out on a perilous quest to find his true self—and a universe of danger.