Short answers, pulled from the story.
In its earliest Hebrew usage, Kabbalah means "reception" or "tradition." The word's meaning evolved over time: after the Talmud, it referred to the Oral Law; in the writings of Eleazar of Worms (c. 1350), it referred to theurgy; and in the major medieval texts, it came to refer to a canon of secret mystical books concerned with the relationship between the infinite God and the finite universe.
Kabbalah emerged in the 12th to 13th centuries in Occitania, specifically in Languedoc, among a circle known as the Hachmei Provence. From there it spread with Jewish communities into Catalonia and Spain. The foundational text of Kabbalah, the Zohar, was authored in the late 13th century, most likely by Moses de Leon.
Isaac Luria, a 16th-century Kabbalist who worked in Ottoman Palestine, is considered the father of contemporary Kabbalah. He introduced the foundational concepts of Tzimtzum (divine contraction), Shevirah (the shattering of divine vessels), and Tikkun (cosmic rectification), which gave Kabbalah a new cosmological framework. Lurianic Kabbalah was later popularized through Hasidic Judaism from the 18th century onward.
The Sephirot are the ten emanations and attributes of God through which, according to Kabbalistic teaching, God continually sustains the universe. Moses ben Jacob Cordovero described them as vessels through which God emanates finite reality from the absolute unity of divine light. They function simultaneously as a cosmological map, an ethical framework, and a diagram of the divine structure underlying creation.
Tzimtzum, meaning Constriction or Concentration, is a concept introduced by Isaac Luria describing the primordial act whereby God contracted infinite divine light to create a void into which Creation could emerge. Without this withdrawal, nothing independent of God could exist. The initial emanation that followed was unstable and led to the Shevirah, the shattering of the divine vessels.
Gershom Scholem was a Jewish historian who, in the mid-20th century, overturned the prevailing academic dismissal of Kabbalah and established the modern field of Jewish mysticism studies. His Major Trends in Jewish Mysticism, published in 1941, remains the standard historical survey of the subject. Scholem argued that the mythical and mystical components of Judaism were at least as important as the rational ones and represented a living current that periodically renewed Jewish spiritual life.