Kabbalah
Kabbalah is the mystical tradition of Judaism, and its great map is the Tree of Life: ten sephiroth, the spheres through which the divine becomes the world, joined by twenty-two paths, one for each letter of the Hebrew alphabet.
Western magic borrowed the Tree in the Renaissance and built on it, and that branch is usually spelled Qabalah. What you'll find here is mostly the Golden Dawn's Hermetic Qabalah, as recorded in 777, with the Sepher Yetzirah, the oldest text on the letters, underneath. Jewish Kabbalah remains a living religious tradition with its own teachers; if it calls to you, seek them out.
The Hebrew letters
Each letter is a path on the Tree, a number, and a picture: Aleph the ox, Beth the house, Gimel the camel.
The archangels of the Tree
One archangel stands over each sephira in the Golden Dawn's tables.