I don't want to overquote, so here's a tease and then go read the rest over at Strahan's post.
Oh, and Strahan also reveals that Eclipse Four will include a story from the wonderful Emma Bull.
The third volume was different again. Responding to the criticism the series had received, I cast my net wider and ultimately I think produced a better book. It’s less centre-of-genre in many ways, but has a consistent feel to it and an overall high quality of stories that helped make it the most successful volume, critically and commercially, so far.
Given that it’s also the one I’m happiest with overall, my intention is to very much continue the series as a follow-on from Eclipse Three. The volume I’m working on now, Eclipse Four, is intended to be a direct follow-on from that book. It will feature some of the same writers, and hopefully will feel similar to Three.