Mundaka Upanisada
The Mundaka Upanishad (Sanskrit: मुण्डक उपनिषद्,) It is associated with the Atharvaveda. It figures as number 5 in the Muktika canon of 108 Upanishads.
It is a Mantra-upanishad, i.e. it has the form of a Mantra. But, as the commentators observe, though it is written in verse, it is not, like other Mantras, to be used for sacrificial purposes. Its only object is to teach the highest knowledge, the knowledge of Brahman, which cannot be obtained either by sacrifices or by worship (Upasana), but by such teaching only as is imparted in the Upanishad. With its beautiful style, lucid metres, serious wording, and lofty feelings each mantra of this Upanishad gives joyous reading. It might have derived its name from the word "Munda" meaning "Shaven Head". The assumption is that if the principal thought of this Upanishad is understood, the illusions of material world will be cut like hairs in the process of shaving; or because mostly monks are audience for its teachings, and since usually monks will have a shaven head, this name might have something to do with that background. It is the first text to mention the six disciplines of Vedanga.
It has three chapters and each chapter is divided into sub chapters which are called "Khanda". In total this Upanishad has 64 Mantras.
