The numbers of people who believe in it, or the length of time that they have, are irrelevant to whether or not they actually do anything real. Billions have believed in astrology for even longer times, yet it's still garbage. As for textbooks, after watching what Texas has been doing for the last couple of years, I'm beginning to doubt them myself. I challenge you to show me one real, scientific study, published in a real, scientific journal, which shows that these alternatives are as valid as conventional medicine. Everything I've seen has shown just the opposite.