I think the readers of the Gita Changes web site will find the following article insightful:
http://www.tolkiensociety.org/tolkien/tale.html
The above article details changes/errors/corrections made during the editing and publishing of The Lord of the Rings books during Tolkien's lifetime.
Furthermore (since then), to mark the 50th Anniversary of the publishing, Christopher Tolkien and others have released a revised edition of Lord of the Rings, which includes: