This, the sixth book in the Imager series, is typical Modesitt - the protagonist fighting against impossible odds with powers well beyond the ken of mortal man. It was not the author' best - this is the story of a campaign, and the protagonist, Quaeryt, uses his exceptional imaging ability to ultimately defeat not just his immediate foes but eventually ... well, okay, no spoilers.
Overall, my sense is that Modesitt has a formula that works for him, but he's definitely beginning to get into a rut with this. The story of the humble man with exceptional powers who eventually becomes a major player is one that he has told innumerable times, to the extent that here, in a middle book without either character creation nor real denousement, you definitely see the story becoming threadbare, for all the details.
I've loved the philosophical discovery and richness of themes and details in most of his stories, but there is little here beyond a fairly uninteresting mystery. Had the story been compressed to about a third the length then incorporated into the logical next stage - which I'd speculate would be about the likely conflict between Quaeryt and his brother-in-law, the King, then I would have recommended this higher. As it was, this seemed like an unnecessary middle act, less of interest than Quaeryt's experience as governor (which was interesting though the demotion at the end felt contrived).
I am looking forward to the next (and hopefully last), book in the series, then would hope that he tries something new - perhaps the tale of a female Recluse black staff.