The present work is the first ever attempt to present all Sandhya and Havana mantras with a scientific significance both in Hindi and English for the Hindi and English speaking readers to understand the scientific import of the Vedic mantras involved in the ritual of Sandhya and Havana. Hope the readers of Vedic prayers will welcome this new edition and immensely benefit themselves with the scientific import of the mantras involved in Vedic Sandhya and Havana to be performed by followers of Vedas and Arya Samaj regularly.