These two books appear to be editions of the same, but for one the author is listed as "Lowell Thomas" and for the other, "Lowell Thomas Jr". I'm not sure of the best way of dealing with this.
The books are already combined under "Lowell Thomas Jr." "Lowell Thomas" has been added as a secondary name to the edition using that version of the name (though a did make a few corrections). This is the correct way to handle authors who publish under multiple names.
http://www.goodreads.com/book/show/26...
http://www.goodreads.com/book/show/27...