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.
The greatest help to spiritual life is meditation. In meditation we divest ourselves of all material conditions and feel our divine nature. We do not depend upon any external help in meditation.
-Swami Vivekananda