Aether Spheres Books in Order

Aether Spheres is Stewart pushing his science-fantasy instincts in a more openly swashbuckling direction. The elevator pitch is easy to like: ships that sail magical currents between worlds, fantasy peoples with their own histories, dragons, prophecy, and the black void between spheres waiting to swallow the unready.

The core trio is Cat Greentrees, Brushfire Hammerhead, and Armand Bluestaves. Cat is an exiled captain who knows his way around command and disgrace. Brushfire brings shamanic strength and a very personal stake in keeping her people free. Armand is an archmage whose visions suggest the danger ahead is far larger than any one court or kingdom wants to admit.

What makes the setting fun is that it treats ships like ships without losing the fantasy. Travel depends on aether currents, void space feels alien and hungry, and the spheres each have their own political and magical texture. You get some of the pleasures of naval adventure, some of the pleasures of epic fantasy, and a strong sense that the characters are operating on the edge of maps that may not be complete.

So if you want a series where the wonder is right out in front, this is probably the one. The stakes are large, but the books stay anchored by crews, command problems, and the question of whether a few improbable allies can get ahead of a disaster big enough to catch entire worlds.