The Tolkien Companion and Guide by Christina Scull and Wayne G. Hammond (now up to 2300 pages!) is
finally supposed to surface in Great Britain on November 2, and shortly thereafter in the U.S. We have been waiting a long time for this. See
here for the announcement in Tolkien News. This time the announcement is straight from Hammond and Scully so it's probably right!
Here is a description of what's coming:
review.