Are the trilogy books you have co-written something that you found enjoyable, or is it difficult to sustain that kind of plot with a tie-in?

Jeff: I think a trilogy is always a challenge, because by its nature it can't be paced out the same as a single novel. With the Unseen trilogy we tried our best to keep the action moving, to make sure that Book Two was a crucial book and not just filler to get from the beginning to the climax of Book Three. And of course, we had some limitations because we had such a huge cast, all of whom needed to be included in some substantial way.

Nancy: A trilogy is a blessing and a curse; it's like having a huge arc in a season. But one of the problems that may arise is that during the time it takes to write a trilogy, the actual season on TV may go in a different way. With Buffy and Angel, there are always surprises! A lot of people think there are built-in limitations to writing tie-ins, but the opposite tends to be true - lots and lots of ripe and juicy choices. Joss and Marti keep us hopping, that's for sure!