Spectacularly good. A fresh fantasy with a well thought out cosmology and a very interesting set of worlds. Barker creates a setting that's at once enticing and foreboding and populates it with a variety of heroes and powers, humans and monstrosities, each with their own very believable drives and failings.

There are worlds beyond Earth—four of them, in fact—separated from Earth by a magical void full of ravenous monsters. Three of them are under the control of a cruel Autarch, who rules from his huge city of Yzordderrex. God seems to have walled himself away in the last of them. Two centuries ago, the greatest magicians of all of these worlds tried to join Earth to them, and caused a catastrophe when they failed. Now an opportunity to try again has come, but what's worse: failure, or success?