Blank Pages Inserted when Printing from a Book
If you have a chapter in your book that comprises a single side of content, then when printing duplex from the book, a blank page will be between the single side of content and the next chapter, regardless of your settings.
That is, your pages print from the FrameMaker book like this:
last page of chapter
first page of single-page chapter
blank page inserted during printing
first page of new chapter
And, you want this:
last page of chapter
first page of single-page chapter
first page of new chapter
To eliminate the blank side, try creating and printing from a PDF or rearrange your content so that you have no chapters that contain only one page of content.
Sean