There are atheist Jews and believing Jews, Israeli Jews and Jews of other nations. There is Sephardic Judaism, Ashkenazi Judaism, Mizrachi Judaism and Falasha Judaism. Reform, ultra-Orthodox or Reconstructionist Judaism. Because Judaism is not only a religion, nor a lineage, nor a nation... but then, what is it? These pages shed light on the first monotheistic religion organized around the temple of Jerusalem, a fact that coincides with the writing of most of the biblical texts. They coexisted with Egyptians, Babylonians, Phoenicians or Sumerians... and when these peoples disappeared, the Jews continue to exist. Their culture, language, laws and religion have remained intact even after being expelled from their homeland and dispersed throughout the world. During their exile they developed special rules for living through rabbinical works, such as the Talmud, which provided them with a moral compass to live by, no matter where they ended up.... Even the Holocaust failed to decimate their faith. This book delves into the evolution of Judaism from a historical-critical perspective, starting from an ancient era in which this conceptual category did not even exist, through the stages in which the Jews ceased to be an ethnic group and a territorial state due to dispersion and proselytism, to the consolidation of Judaism as a religion in the modern sense of the term, as a set of beliefs and ritual, moral and ethical practices linked to the spiritual and the divine. Without knowing the past and present of Judaism it is not possible to predict its future, nor is it possible to understand the origins of Christianity or Islam. The author reflects on the historical links and relationships between the three great monotheistic religions. This is the history, the culture, of the rich and diverse Jewish identity.