Judaism is the original of the three Abrahamic religions, which also includes Islam and Christianity and has around 13.9 million followers worldwide, with members in Israel and the United States accounting for 82% of the total population. Israel is the only Jewish majority country and Jewish state in the world. In 1939 the Jewish population was at it's largest, with over 17 million Jews worldwide, however due to the Holocaust, this was reduced to 11 million in 1945. By the 1970s this had grown to 13 million, before plateauing because of assimilation and fertility rates. Since 2005 there has been modest growth in population of about 0.78% because of the rapid expansion of the Haredi and other Orthodox sects. There is some debate over numbers, partly due to differing opinions on what 'makes' someone a Jew. Some insist that the Jewish identity may only be passed down through the mother, while others recognize those born to Jewish fathers as member and those who have chosen to renounce their faith.

Judaism began in the Middle East around 3,500 years ago and was founded by Moses when God bestowed unto him sets of rules and guidelines, including the Ten Commandments. However, Jews trace their history back further than this, and the story is told in the Old Testament of how God chose Abraham to be the father of a chosen people who would be an example of holiness to the rest of the world. After Moses, God stayed with the Jewish people and under his guidance they became a powerful people with Kings such as Saul, Solomon and David who built the first great temple, which became where Jewish worship was centered around and contained the Ark of the Covenant. Their Holy book is called the Torah, and there is also a comprehensive written collection of Jewish oral law called The Talmud, which are both written in the language of Hebrew.

Jews believe that there is only one God, who created the universe, is everywhere and all-knowing. Jews have a covenant relationship with their God; in exchange for all that God has provided and continues to do for them, Jews promise keep God's laws and bring holiness into their lives. Jewish tight-knit communities reflect the community and family-mindedness of the religion. Many activities like worshipping in the synagogue (a Jewish church) or weddings are done as a community, and inclusion into faith and family is done from an early age. Boys are circumcised at 8 days old in accordance with the instructions God gave to Abraham 4,000 years ago. A lot of Jewish holy days like the Sabbath, Passover (celebration of the Jewish slaves escaping slavery in Egypt), Rosh Hashanah (celebration of the creation of Adam and Eve) and Yom Kippur are heavily centered around the family and involve the children.

Being a part of a very religious community means religious Jews have avoided assimilation, and this is seen in the distinctive practices and dress of very orthodox Jews, known as the Haredi. The Haredi often wear black, distinctive headdresses and the women cover their hair with scarves, hats or wigs after they are married and dress conservatively. There are a spectrum of Jewish cultures and denominations, including Reform Judaism, Modern Orthodoxy, Humanistic Judaism and Liberal Judaism, which all vary in terms of strictness and interpretation. There has been a renewed interest in Orthodoxy recently as Jews seek to explore their religion and relationship with God through a greater knowledge base. Clothing varies by denomination, but often Jewish men will wear a skullcap called a kippah or a yarmulke as a symbol of their devoutness and identity, and most Jews will cover their heads when attending synagogue, religious events or festivals. The Jews also have a set of dietary laws, and permitted foods and methods are commonly known as Kosher. Animals like pork, fish without fins and scales, hares and bats are banned, and milk and meat are not mixed. Some orthodox kitchens even have two sinks to ensure that neither is tainted.

The leader of the community will vary depending on the branch or location, however in most synagogues the Rabbi will assume the most senior spiritual position and in Hassidic communities this role may be hereditary. Other leaders are appointed or elected. Chief Rabbi is a very senior role in the government of Israel, and many other Rabbis, famous Talmud scholars are also highly influential. Due to the variety of Jewish practice and lifestyle there are also large bodies concerned with the welfare of followers such as the Antidefemation League, American Jewish Congress and American Jewish Committee.

The aim of Judaism is not just to simply adhere to rules blindly, but to incorporate good, just actions into one's everyday life and to be good person as part of a community. Instead of the word 'I' and 'me' being included in prayers and blessings in religions like Christianity, 'we' and 'our' are much more common, indicating the sense of community. There is very little written down about the afterlife in Judaism, and while most Jews are in agreement that death is not the end, the rest has been largely contested and speculated upon. There will be an 'end of days' and the idea of the Garden of Eden (not the place Adam and Eve are from but a place of paradise) some mystical strands of Judaism like Kabbalah discuss the idea of reincarnation, but the ideas on the afterlife are vague and dependent on the denomination of Judaism in question. Judaism is strongly focused on doing good deeds in life rather than what comes after, and sees the ultimate goal of creation as altruism. The famous Rabbi Abraham Isaac Kook says that love is the most important attribute in humanity. The act of giving, or bestowal is seen as an act of altruism that therefore serves God. Kabbalah defines God as the force of love and giving in existence. Modern Kabbalah saw these ideas developed and focuses on how society can create an altruistic framework for it's betterment.