The Tree of Life
Etz Haim (the Tree of Life) is the best instrument to understand a reality, a person, a situation. The Tree of Life is made of 10 Sephiroth connected by 22 paths. Sephiroth (or Sephiroth, Sefiroth, Sefirot) literally means “enumeration” and is the plural for Sephira. They are Powers of the Soul. The 22 paths are the 22 letters of the Alef-Beit, the Hebrew Alphabet.
Kabbalah says that one reality expresses itself through its nine attributes, which means that you can easily project on the Tree of Life anything that has an essence and a manifestation. It is the clef of a staff of 10 descending notes (the Sephiroth) that starts from a cause (Keter) and ends to an expression (Malkhut).
For instance, if you want to understand a man through the help of the Tree of Life: Keter is the Spirit; Hokhma is the capability to perceive and dream; Bina is the capacity to rationalize; Hesed is the way he loves; Ghevura is his power; Tiferet is his equilibrium; Netzah is his self-confidence; Hod is the capacity to lose; to lay aside and be with the others: Yesod is his sensibility and sexuality; Malkhut is the body.
It all sounds a bit complicated but, to help you understanding, I have prepared a video about the creation of Etz Haim and the Sephiroth.