Gayatri mantra is a Vedic prayer. It is a universal prayer that can be used by any person, belonging to any country, irrespective of race, religion, or sex. This book includes the symbolism of Om and the Gayatri, the scriptural references where they are mentioned, as well a detailed instruction on how to perform the Sandhya rituals. Text for the rituals is in Sanskrit with transliteration, and English translation.
My child, what I want is muscles of iron and nerves of steel, inside which dwells a mind of the same material as that of which the thunderbolt is made.
-Swami Vivekananda