I can not say this is a "modern classic"; but it is enjoyable. I read thinking this was historical fiction, but it's actually an "alternative" historical novel. There are clever little turns of phrases, such as "men and only men" to distinguish from "the Others" (which are clearly a Vampiric trope).
There are some enjoyable Characters, my interest was pipped by the woodsmen, and I would like to know more about them, they're adventures and history possibly have a few books in them themselves!
There a number of minor grammatical and phrasing issues - e.g. there is the use of a singular 'bear' when the plural 'bears' is meant. There is also a sentence end without a beginning "doctor in Sheffield." However, these issues aside, this short novel reads well, quick and engagingly, with great characters, a fun story and I look forward to reading the rest of the series.