Thousands of years in the future several civilisations face similar problems and one mystery ties them together for good or bad. An interesting read, from a New York Times best selling author, after you get past the confusion of several stories intertwining.
In the Empress of Eternity there are several civilisations set at different times with their stories told interleaved. The approach makes sense after you realise what is happening. The characters and situations are similar to the point of confusing the different stories. Just when you start to sort them out, they start to intersect. The final chapters are worth the work through the earlier chapters.
The author, L. E. Modesitt Jr. received good reviews for the earlier The Magic of Recluse. I have not read The Magic of Recluse and, after reading Empress of Eternity, will look for some other books by the same author.