Myth of the Goddess
The latest cool book I have read. This one is fascinating. Tells the real tale of how symbology has evolved over the last 20,000 years. When you start back that far, you realize the the last 2000 to 4000 years of patriarchal religion is actually fairly new. There is a much longer human history of egalitarian, nature-based religion.
The books of Marija Gimbutas are next. She was a great archeoligist and mythologist who studied Old Europe.