The Muktikopanishad referred to 108 Upanishads and among them it identified Isa, Kena, Katha, Prasna, Mundaka, Mandukya, Taittiriya, Aitareya, Chandogya and Brihadaranyaka Upanishads as principal Upanishads, the reason being that they expound the spiritual wisdom – adhyatmavidya comprehensively. Four among these Upanishads contain what are popularly referred to as Maha Vakyas – great statements whose direct and stimulating philosophical message is for all people and all times. Their universal and eternal appeal inspired every thinker's mind and even today they survived the scientific advancement and the so called rational thinking and enjoy unparalled sway in philosophical thought.
These Mahavakyas and several other sayings in Upanishads are frequently quoted by the Pandits who lecture on Puranas and spiritual topics. As all these ultimately form part of Vedas only, they teach eternal values – Sanatana Dharma. So we are publishing this small booklet mainly with a view to disseminate the eternal values contained in the Upanishads, briefly, so that these ideas flash in the minds of those who need them at the crucial moments in their life and guide them along the path of righteousness. If parents take interest and see that some of these sentences are committed to heart by their children, surely the path they take in life would be the right one that leads them to sure success.