action adventure adventureandadventurers children'sfiction delphianoracle fables fantasy fantasyfiction fiction general gods godsandgoddesses greek greekgods greekmythology juvenilefiction legends magic mythology myths newyorktimesbestseller nyt:childrens-middle-grade-hardcover=2016-05-22 percyjackson quests(expeditions) rickriordan roman thehiddenoracle toa