The Zoom-In
 

I was looking at the map in the back of my copy of RotK(which I have just now started calling The Zoom-In), and I noticed up in the corner there are the initials C.J.R.T. Why is that? Did Christopher Tolkien draw up that map, or did he make a rough sketch that Chris refined for publication or what? I haven't checked the Hobbit, but the initials are not on the other two LotR maps(or I guess the other one, since they're the same). Does anybody know what it means? Any info on this would be helpful.

Yes, the topographical map of Gondor, Rohan, and Mordor in the back of the Return of the King was drawn by Christopher Tolkien. So, for that matter, were the original maps included in The Fellowship and The Two Towers, until the publication of Unfinished Tales, and the redrawing of the map, which was then included in new editions of The Lord of the Rings.

J.R.R. Tolkien drew the original, rough maps that served him well as he wrote the books, but these maps were very battered, much emended, and unsuitable for publication for reasons of their coloration anyway. So he had Christopher redraw them.

However, the map in The Hobbit was done by J.R.R. Tolkien himself.

In the U.S. authorized paperbound edition FOTR and TTT by Balantine are maps drawn by a Shelly Shapiro '88 (I assume year 1988); in RotK it is Christophers maps. Does anyone have info on her?

The Zoom in
 

I could be wrong but my guess is that the initials are those of Christopher Tolkien. JRR was calle John Ronald Ruel (hope I@ve spelt that right) so perhaps the J and R of the initials on the map are Christopher's middle names, after his Dad

Christopher John Ruel Tolkein.

So yes, and I think that was the assumption made. If my Tolkienology is correct, he would have been the only Tolkien child still at home if not getting ready to leave home at the time of the end of writing The Lord of the Rings..

But here is the official line taken from My one volume edition of The lord of the rings;