Thank you for writing to us about the availability of a NOOK Book format for the book "Rise of the Dark Angel" by Carol Brearley.
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So, it looks like it is all down to the publisher to decide, which means it will not be until at least October 22, 2012 (when my KDP contract ends) before the publisher will even consider it. For now, all I can recommend is to go to the print version on Barnes and Noble's website and click on the link "Want to read this on your NOOK? Request as NOOK Book from the publisher."
Wish there were more I could do.