I am trying to upload my PDF to Blurb to create a 8x10 trade book, but it is not clear to me if the cover and interior pages need to be included in the same PDF file or different PDF files. I created the book using MS PowerPoint 2010 software and have saved the document and ImageWrap cover as two separate documents. Blurb specifies that for the 8x10 trade book, the ImageWrap cover PDF should be 18.25 x 10.861 inches and the interior pages PDF should be 8.125 x 10.25 inches. That seems to indicate to me that these need to be two separate PDF files. Is it even possible to create a PDF file with different size pages in the same file? The instructions on the Blurb webpage are vague on this point. The instructions seem to indicate that the cover should be page one of the document, but that point is not made explicitly clear. The instructions also say to make sure the document contains an even number of pages, but does that include the first page as the cover? That is not clear. The most logical approach to me is to upload two separate PDF files - one for the cover that measures 18.25 x 10.861 inches and one for the interior pages that measures 8.125 x 10.25 inches. Is that what Blurb expects? Or do they want a single file with the cover as the first page with different sizes set for the first page (cover) from all the remaining pages. And if so, does that cover then count as one of the pages in the overall even page count? Or not? Thanks for any help or advice on these points.