Magic (including libriomancy) has been revealed to the world... and not everyone's happy about it. As Isaac deals with politics, terrorist attacks of inhumans on magic-opponents seems to indicate that war is inevitable, but perhaps things aren't as clear as they seem...
After the previous three books, this one took an entirely new direction, but that just made it fresh, interesting, and still exciting. The plot barrels along quickly, there's action aplenty and it's a great read from start to finish.