Price: 1100 Yen ISBN: 978-4-06-375580-0 Secret door of 'Inhabitants of the Infinite' opens now ... as the first guide book finally appears. Gorgeous, special project. It talks about the production secret story and motivation. Interviews of the makers. Additionally, autograph comment by cast formation is published. This fanbook include plenty of contents of enhancement like the glossary, set material, event reports, story & character introduction!