Engine Summer by John Crowley

In the drowsy tranquility of Little Belaire, the Truthful Speakers lead lives of peaceful self-sufficiency ignoring the depopulated wilderness beyond their narrow borders. It is a society untouched by pain or violence and the self-destroying ‘Angels’ of the past are barely remembered. But when Rush That Speaks leaves his home on a pilgrimage of self-enlightenment, he finds a landscape haunted by myths and memories. The overgrown ruins reflect a world outside that is stranger than his people ever dreamed …