So I went to B&N because I had a coupon. I wanted to pick up the next book in the Earth's Children series. They had copies in trade paperback and mass market.
In a moment of complete OCD, I bought the entire series to make sure my books match when I put them on my shelf.
In a related note, I know I'm like thirty years to late, but I really love this series. I'm almost done the first book, Clan of the Cave Bear by Jean Auel.