State of Change is an original novel written by Christopher Bulis and based on the long-running British science fiction television series Doctor Who.

But something is very wrong: The tomb walls depict steam-driven galleys and other disturbing anachronisms.

The time travellers discover that Rome has advanced far beyond its natural means, and they must recruit the aid of Ptolemy Caesar to prevent his half-siblings, Alexander Helios and Cleopatra Selene II, from waging a potentially world-ending war with each other.

But the anomalies don't just end with Rome, as The Doctor and Peri experience changes of their own...

It is implied at the end of the novel, when the Dominion is transported to a newly created duplicate of Earth in a distant star system, that this is the same planet as Mondas - the eventual home of the Cybermen.