This Upanishad belongs to the Atharva Veda. As the name of the Upanishad suggests, the teachings revealed in it are such as to leave its students clean, like a shaven head (mundaka), rid of the veil of ignorance. The lucid translation of the text along with Shankaracharya's commentary on it is an additional aid to comprehend the profundity of the subject.
Understanding human nature is the highest knowledge, and only by knowing it can we know God. It is also a fact that the knowledge of God is the highest knowledge, and only by knowing God can we understand human nature.
-Swami Vivekananda