The Zohar is the name of the Light that comes from the head of Arich Anpin, which is the state of the end of correction. The Zohar was composed by ten great Kabbalists who represent the ten main Sefirot, the complete HaVaYah. This is the original Upper System which descended to a particular level, and later, Baal HaSulam brought it even closer to us. As a result, we have a connection with the highest state. All of this was done for us.
Talmud Eser Sefirot is a special book. However, it is written in a form that distracts our mind so much that we cannot bring our feelings into it. Perhaps after reading The Zohar, we will be able to begin to read Talmud Eser Sefirot properly. The Zohar addresses our feelings and the Sulam Commentary addresses our minds. Together, they stir us in both of these directions and we are unable to resist it.
The Zohar is a revelation of the Upper System where you are allowed to press the buttons controlling everything. Even though you don’t know what buttons you are pressing, the system translates them into the proper influences. The Upper Degree (or a Kabbalist) understands what you want. He doesn’t give you what you are asking for, but what you really need. He acts in accordance with your inner need. For this reason, The Book of Zohar is the most special book of all the books of Kabbalah.