I noticed that one of the authors has posted a comment here:
http://www.tolkienguide.com/modules/...ode=0&start=10
In particular, they say:
"We wanted to include various letters in the book, some from members of Ronald's family, or failing that to give some account of their contents to illustrate how close and loving the family was and what they talked to each other about. This has been the sticking point that it has not been possible to overcome thus far.
I should also point out that the Estate have not been demanding money for permissions or anything like that."
AND
"The publication of the book had to be cancelled as there was not time to make further changes to the book and get it printed and bound in time for the launch. What happens in the future I really don’t know. Only time will tell."
So the book may still be published in the future.
The problem the Estate has is the publication of the letters - either in their full form or in paraphrased form.
Some have suggested that it is not a violation of copyright to paraphrase material -
but that depends. For example, it is not a violation of copyright to do a 1000
word paraphrase of
The Lord Of The Rings, but it would definitely violate copyright to do a 1000
page paraphrase of
The Lord Of The Rings, because that would simply be an obvious
rewrite of the book, which most definitely
would not be allowed!