perfect haiku in an sf novel. Some of his fantasy and sf has historical settings.
A supernatural or extraterrestrial being should not make its frst appearance on the last page of a historical novel unless the text has built towards such a conclusion. A medieval monk can display detective skills but again should not do so for the first time on the last page. (All such generalizations are vulnerable to a writer doing something original that works.)
History past and future is a single process as Poul Anderson shows in his time travel novels and in The Boat Of A Million Years. Also, history might be not only Terrestrial but also galactic. Anderson's Terran Empire is modeled on the Roman Empire and incorporates remnants of an Ancient interstellar civilization. In Larry Niven's Known Space future history:
Terrestrial human beings are mutated Pak breeder colonists of a former Slaver food planet;
Slaver artifacts and even a live Slaver are retrieved from statis fields;
Jerry Pournelle and SM Stirling add another live Slaver and a tnuctipun rebel;
Anderson adds a tnuctipun weapon comprising an enclosed black hole.
Past and future interact as do sf writers.