'Imperial Moon' is a Doctor Who story set in 1878, which features the British conquest of space by its first manned moon flights. Whether this is an alternate universe, someone tampering with history, or some other explanation is one of the nubs of the story.
Being set in 1878, Christopher Bulis has drawn from the literature of the time for the feel of the story. The ghosts of Jules Verne, H.G. Wells, H. Rider Haggard and Arthur Conan Doyle appear to have been whispering in Mr. Bulis' ear. However, in advancing the story and bringing it to its conclusion, it is contemporary science fiction of Doctor Who that sets the tone.
The Doctor is in his fifth incarnation (portrayed on TV by Peter Davison) and is assisted by the less than trust-inspiring pairing of Turlough (who joined the TARDIS crew to kill the Doctor for the Black Guardian) and Kamelion (a former slave of the Master). Like in real life, Kamelion plays a relatively minor role (the Kamelion robot proved too problematic to use prominently in filming the series), so it largely falls to the Doctor and Turlough, and their astral mariner allies, to deal with the mysteriously populated jungle crater on the lunar surface.
The novel has obviously been well thought through by Mr. Bulis, who displays his influences proudly, and the moral dilemma of Turlough is well-portrayed and within the established scope of his character. The portrayal of the Victorian characters is good, and I especially enjoyed the inclusion of Queen Victoria and her gillie, John Brown, who open the book and... but that would be telling! Captain Richard Halliwell and Miss Emily Boyes-Dennison, who carry a moderate portion by themselves, appear to be included in part to show the impact of the "New Woman" on Victorian society.
I found it a good read, which I believe would benefit from close attention however having the advantage of not requiring it. It seemed well-suited to the Davison-era of Doctor Who, although perhaps earlier than it is set as it doesn't suffer from the efforts of the script editor of the season it was set in trying to make the show more "grim and gritty"...