The Plains of Passage by Jean M. Auel (audio)

★★★★

"In a world so empty of human life, there was a comfort in the thought that an invisible realm of spirits was aware of their existence, cared about their actions, and perhaps directed their steps.  Even a stern or inimical spirit who cared enough to demand certain actions of appeasement was better than the heartless disregard of a harsh and indifferent world, in which their lives were entirely in their own hands, with no one else to turn to in the time of need, not even in their thoughts."

 Earth's Children #1 - The Clan of the Cave Bear

Earth's Children #2 - The Valley of the Horses

Earth's Children #3 - The Mammoth Hunters

So begins book #4 in the Earth's Children series.  This one not only includes your "daily dose of caveman porn," but there's mammoth porn as well.  And Ayla and Jondalar give Anastasia and Christian a run for their money!

The Plains of Passage starts as Ayla and Jondalar leave the Mamutoi to begin the long-awaited journey home to Jondalar's people.  They travel with wolf and their two horses through present-day Europe where they meet many different groups of people.  Although they encounter some difficulties, they are generally well-liked by the people they meet.  As they leave each group behind and head west, Ayla wonders if Jondalar's people will be as excepting of her.