"The Christian Bible is like a drug store, Mark Twain wrote. The stock remains the same, but the medical practice changes. Christians tend to be embarrassed by (or to deny entirely) the extent to which their religion has changed over the centuries, but they shouldn't be. In generation after generation, people have faced challenges unforeseen by their ancestors, and though they have often needed to discard the ideas and practices that had been handed down to them, they have been able to find in the Christian myths, symbols, and sacred texts the wherewithal they needed to construct a viable religion for their times "