The Holy Science

"The Holy Science" was written by Sri Yukteswar at the behest of Mahavatar Babaji. In it, Sri Yukteswar compares Sanskrit slokas to the writings of the New Testament. Also explained is the great cycle of world ages (yugas). Yukteshwar was an educator, astronomer, a Jyotisha (Vedic astrologer), a yogi, and a believer in the Bhagavad Gita and the Bible. He was a disciple of Lahiri Mahasaya of Varanasi and a member of the Giri branch of the swami order.

"The purpose of this book is to show as clearly as possible that there is an essential unity in all religions; that there is no difference in the truths inculcated by the various faiths; that there is but one method by which the world, both external and internal, has evolved; and that there is but one Goal admitted by all scriptures." —Swami Sri Yukteswar Giri

Yukteswar was an educator, astronomer, a Jyotisha (Vedic astrologer), a yogi, and a scholar of the Bhagavad Gita and the Bible.
Yukteswar's teacher guru, who guided his spiritual development, was Lahiri Mahasaya.
In 1894, Lahiri Mahasaya's guru, Mahavatar Babaji, asked Yogteswar to write a book on the underlying harmony between Christian and Hindu scriptures. Yukteswar's book 'The Holy Science' was thus written.
Yukteswar took on many disciples. Most famously, he was the beloved guru of Paramahansa Yogananda, who brought Yoga to the West through moving to America, and through his book, Autobiography of a Yogi , which mentions Yukteswar extensively.
Another of Yukteswar's disciples, Satyeswarananda Giri , also wrote yogic books at the encouragement of Yukteswar.