Book 1 of a 5 book series. Top selling children's debut of 2008. Paperback presented in an orange slipcase. First edition, first printing with full number-line 1 3 5 7 9 10 8 6 4 2. Signed, first lined, dated & stamped by M. G. Harris to the title page. Both the paperback and slipcase are new in fine unread condition.Also included is an Invisible City postcard.