The Clan of the Cave Bear, by Jean Auel
I suppose The Clan of the Cave Bear should be called “prehistorical fiction” rather than “historical fiction.” It takes place in humanity’s ancient past, before the invention of writing and historical records. The first in a series of six, this novel follows Ayla, a Cro-Magnon girl (an ancestor of modern Europeans), as she is adopted into a group of Neandertals. The Neandertals (which are either a subspecies of Homo sapiens, or a different species of Homo—experts aren’t sure) are destined…
