How did Judaism survive the diaspora?

Two other related aspects of Judaism were quite important, too. First was that the Torah was central to Judaism, the reason Jews are called the people of the book. The fact that a book was more important to Judaism than any other physical object or place made it easy to carry the religion with people wherever they went.  Little is more portable than a book.  Second, the idea of having a rabbi-centered form of Judaism, rather than a priest-centered form of Judaism, allowed for a democratization of the religion and an independence from just one temple, a kind of decentralization, instead of a dominant priestly caste that was dependent on one temple in one place that could be and was destroyed.  Rabbis were the teachers, not simply religious leaders, and as such, they ensured that all males (and now females, too) learned to read the Torah and observe all proper prayers and rituals. Had the religion not made this paradigmatic shift from priest to rabbis, so that all Jews could read Torah and be properly observant, it is quite possible that Judaism would be no more.