Unify and split master pages

Some master pages have left and right versions to match the book margins on the left and right facing pages. You can select a left or right master page and consolidate the two versions into one page.

Unify left and right versions of a master page

Select a left or right master page in the Master Pages pane of the Book Layout Editor.
Choose Unify Master Page from the Book Action pop-up menu .

Split a master page that doesn’t have left or right versions into left and right versions

Select a master page in the Master Pages pane of the Book Layout Editor.
Choose Split Master Page from the Book Action pop-up menu .

You can now adjust the position of items on the new pages to match the margins on the left and right pages.