Do these books rely upon lots of photos?
If so, it may be that the books were created for SVGA resolutions (800x600), and are being rescaled when displayed on an HD device (the HD+ has over 4X the pixels, so what was one pixel on an old device is sized up to take four pixels).
... Cookbook formats on HD+ ... look great on my old Nook Color? ...
Anyone have a suggestion for a good Muffins Cookbook?
Makes sense but problem is that BN does not always tell you what a book was formatted for in the book description lol.