There the sun shines not, nor the moon, nor the stars; lightnings shine not there and much less earthly fire. From his light all these give light, and his radiance illumines all creation.
The Mundaka Upanishad is one of the earlier, "primary" (mukhya) Upanishads. It figures as number 5 in the Muktika canon of 108 Upanishads. It is a Mantra-upanishad with three chapters, and each chapter is divided into sub chapters which are called "Khanda." In total this Upanishad has 64 Mantras.