So, I've been at this long enough that I have to stop and think about how many novels I've actually published. (answer: 13, plus 2 collections) It's a milestone of sorts.
I find I've been inadvertently confusing people, because with the release of Kitty's Greatest Hits, there are actually 10 Kitty books on the shelves. However, 9 of them are novels, and Greatest Hits isn't (it's a different format and everything). So I haven't been counting Greatest Hits in the sequence when I number off the novels, because it includes work written over the last ten years, and its continuity is all over the map, from 500 years before the novels take place on up to the recent ones.
So, when I talk about Kitty #10, I'm not talking about Greatest Hits (even though, technically, it's the tenth Kitty book). I'm talking about the tenth novel, which is Kitty Steals the Show, which is coming out this summer (woot!). #11 is the novel after that: Kitty Rocks the House, which I have just turned in and will probably come out in about a year or so. And I've just started work on the one after that, which is #12.