Rudyard Kipling Poetry

It seems there's a new collection of various verses from Rudyard Kipling that are going to be included in a new Cambridge edition being released this week.  Now, one must wonder, given the prolific nature of Kipling's work--was there a reason these pieces were not published previously?

One group is described as being humorous verses that seem to have been composed on the fly to entertain his fellow passengers on a sea voyage. It is easy to imagine that the author never intended those to be among his "greatest works", but amusing they might be.

Sometimes the fact that we can find work that was not published prior may be subverting the author's own intentions concerning how his body of work was to be remembered.

http://www.guardian.co.uk/books/2013/feb/25/rudyard-kipling-poems-discovered