Understanding Safe And Bleed Areas

On the Book Editing page, the dark gray border around the book page shows the actual trim area; any elements that extend into this area will be trimmed off the page. Therefore, do not place any elements (text, photos, clip art) in this area unless you want them to bleed off the page. 

The inside, lighter gray border represents a safe area. It is also recommended that you keep any important elements out of this area, to prevent them from inadvertently being trimmed off the page.