On Thu, 9 May 1996, Damon Jason Casale wrote:

Anyone know how far Xanthony's gotten on his Magic of Xanth series?  Last
I knew, he was up around book 14 or so (and this was a few years ago),
and still going.  After reading a couple of those all the way back in
Junior High, I couldn't stand his bad humor any more.  His other stuff
was decent, though...

18.  And he said that wasn't the end.