With its characters often being fictional, a historical novel,with its narrative set against a background of real conflicts and issues in time, often elicits interest from a reader who would normally not pay much attention to the mere recordings of historical fact that form the background for the narratives. Thus, as a secondary benefit, the reader of a historical novel learns much about a historical era.
So, historical novels are novels that both entertain and instruct. For instance, a classic novel such as A Tale of Two Cities by Charles Dickens gives a reader a history of the cruelty and bloodshed of not only the French Revolution, but also the age of highwaymen and grave robbers in England. The Irving Stone novel, The Origin, provides a delightful narrative about Charles Darwin the man, along with his influence upon science.