Men's Greatest Inquiry is the revised and enlarged edition of the book Eternal Question 'Who Am I' published in 2004, which was appreciated by all the readers. Since the beginning of men's life it has been the greatest puzzle for all. But the great Rishis, who realized God, answered this question. None of the religion or any philosophy except Sanatan Dharma answer this question. All the world philosophies stops at this question. In fact the Hindu Dharma starts with this great question. This book has been written with the sole aim to serve the humanity & God. Author has tried his best not to twist any spiritual, religious, scientific and historical fact. Truth should never be twisted to please someone. I have the blessings of the great saints like Sri Amar Jyoti Babaji, Mahavatar Babaji and Sri Sathya Sai Babaji, who are self-realized Saints. Sri Adi-Shankarachariya answered this question when he was only 8 years old in the highest philosophical eight verses in Sanskrit. Generally, the western authors are deprived of such opportunity. Sh. D.V. Mangla, Auhtor of this book is M.Sc. M.Ed. PGDCA got his master's degrees from university of Delhi.. He is an extraordinary combination of spiritual & scientific bent of mind. He joined his Ph.D. in Mathematics at Delhi University in 1969. He used to discuss about God, Shastras and Science and this great question with various saints and scientists. He has fully devoted his life in the pursuit of God, spiritual studies and yoga practices. He served as lecturer in Mathematics at University of Aden and worked as Principal in Delhi.He is disciple of Paramhans Yogananda and practicing 'Kriya Yoga' since long. He is a scholar of Science, Mathematics, Education and Philosophy. He has the ability to correlate Sciences, Shastras, Spiritual Science and God. His books are rare masterpieces based upon his spiritual experiences and vast studies and useful for believers and non-believers. Only the Vedas and Upanishads helps the seekers of God to answer their personal philosophical queries. Buddhism and Jainism doesn't believe even in God and have no literature about God. Bible: both Old and New Testaments are simply collection of various Historical events narrated by ordinary persons arranged in Chronological order. These neither tells anything about God, nor philosophy nor the question "Who Am I"? Why I dream? What is death? What is rebirth? Who takes rebirth? Why do we suffer in life? Why some are born with silver spoons get everything without any struggle in life? Where will I take my next birth? Will I be a human or some other living being?