When the third volume came around I was too busy and didn't try.
For the fourth, though, I was determined to send something, and after much effort I managed to write "Sorcery of the Heart," which they bought.
That was suffiently enjoyable for all concerned that they invited me back for Volume 5, and I came up with "An Interrupted Betrothal," and they bought it.
Alas, as of this writing no sixth volume is planned.
That's it; here's your list of handy exits: