Puffin, New York, 2004, 1^st pr thus.  ISBN 0-14-240216-8.  Soft cover, 213 pages.  Unread remaindered copy; light edge and cover wear, sticker on rear wrap.  ‘Hercules Amsterdam may sound like the name of a heroic strongman, but he’s actually a ten-year-old boy no bigger than a mouse.  One day, Hercules discovers that a passageway behind his bedroom wall leads to a fanciful miniature city – full of mice.  Hercules quickly falls in love with the carefree ways of the mice, and it’s not long before he feels more like a mouse than a boy.  But when Hercules stumbles across abandoned cities that look like war zones, he realizes that the mice live with a frightening hidden threat – rats!  Hercules is determined to protect his sweet, gentle friends, but how can he when he is only three inches tall?’ (from rear wrap)