Ayla is a young girl orphaned by an earthquake in prehistoric times. Only five and left to wander helplessly looking for food and water, she is attacked by a cave lion before chancing upon a group of Neanderthal. Taken in by the medicine woman, Iza, and the holy man, Creb, Ayla is bought up as a Neanderthal, as one of the Clan. But despite her best efforts she is different and finds it hard to conform to all of their customs and rituals. The leader, Brun, is accepting and lenient, but the future leader Broud, develops a deep resentment towards Ayla. As she comes of age her differences become more apparent and tensions appear in the Clan. As they prepare for a Clan gathering with other groups of Neanderthals, things build to a head for Ayla and her adopted family.I was ambivalent about The Clan of the Cave Bear. I found it to have a very slow start and it took me a good hundred pages or so out of five hundred to actually get involved with the story. It was hard to connect with Ayla properly until she was a bit older, but once I had connected with her I started enjoying the book a lot more as I did want to find out what would happen to her. The first time she got into trouble with the Clan, I was gripped, but as the book went on the structure became a bit repetitive. It basically went like this: Ayla breaks a Clan custom because she is different, Broud wants her to have a death curse, the men have extended deliberations, Brun finally decides to accept Ayla back. This happens two or three times and so the tension was lost; Ayla didn't seem to be in any danger of being cut off from the Clan whilst Brun was in charge.I admire the world building in The Clan of the Cave Bear. The prehistoric times are bought back to life vividly and it's easy to tell that Auel has thought about every aspect of Clan life and ritual before writing. The slow pace meant that this world could be fully introduced and also that there was time for all the characters to shine and be developed, not just Ayla. I was fond of the leader, Brun, and the calm, logical approach he took to the people he was responsible for. Even the villain of the piece, Broud, is a balanced character and Auel takes the time to explain his motivation for acting in the way he does towards Ayla.In fact, my main issue with The Clan of the Cave Bear was how long it took for me to read it - almost two weeks. This is unheard of for me, even if I did choose to read it during a busy time at work. To put it into perspective - I read Anna Karenina faster than I did this! And even more so than the time it took, Cave Bear felt like an effort to read and get through. There was so much background information that it became dense and at points it took me days to get through a single chapter. I wanted to finish it because of the characters and world building, but it was hard work and a book like this shouldn't be. So whilst there was a cliffhanger ending and I am interested to see what Ayla will do next, I'll hold off reading Valley of the Horses for a while yet.