I have a book consisting of about 15 chapter files. Due to technical changes outside my control, I need to shift the margins, my ruler makes and all the contents of the left pages only about 1/4" outwards.
What is the easiest way to do this?
Make backup copies of everything first, just in case.
Then go to Layout > Layout Adjustment... and turn on Layout Adjustment. If the text frames are currenly sanpped to the margin guides you're golden, otherwise you need to make two adjustments.
On the master page, if the frames are already snapped to the guides, go to Layout > Margins and Columns and just reset the margins. The frames will move. If the frames are not snapped to the guides, you need to first move the margins so they correspond to the frame edges, then move them where you want. Other master items may need to be moved on the master pages, and objects that don't snap on guides onthe document pages will need to be dealt with individually, but layout adjustment should get you most of the way there.
This worked well. It was a bit tedious having to go through 300 pages and move figures but otherwise worked well.