Onto the fertile but generally unattended ground that lies between the tower of religious fundamentalism on one side and the pillar of secular modernism on the other, as if riding on a light beam descending out of the early 20th century comes Albert Einstein, dimly resembling in appearance the more recent, fictional “mad scientist” played by Christopher Lloyd in the “Back to the Future” films.

Based on the recent release of Einstein’s private letters, CNN Chairman Walter Isaacson has penned a biography about perhaps the greatest scientific mind ever. “Einstein, His Life and Universe” has rocketed to the top of the New York Times’ Best Seller list.

Einstein (1879-1955), the discoverer of relativity, of E=mc2, of the interactive interrelationship between time and matter, a frizzy-haired celebrity in his own time, made his most significant scientific discovery observing a solar eclipse in 1919.

It came just in the nick of time. More than Babe Ruth’s baseball heroics or motion pictures, this profound discovery quickly supplanted the utter despair that arose out of the unspeakable slaughter of men and civilizations that was the Great War.

With the Industrial Revolution, western civilization enjoyed the better part of a century’s worth of generally unbroken progress, in the application of science, engineering and industry to building cities, commerce, infrastructure and breakthroughs in medicine and the arts.

The proud optimism that was associated with this relentless advance came to a horrendous, crashing halt as the very fabric of European civilization was ripped to shreds. The world descended into the carnage of the Great War and Spanish flu pandemic. The costs could not have been dearer. The death toll is put at 66 million.

When the dust settled, a confused, self-doubting humanity was faced with myriad dislocations and, more unsettling, a dark side to its nature that seemed destined to doom hopes for a better world in the long run.

While cynicism and hedonism, on the one hand, and brutish authoritarianism in politics and religion, on the other, became offsetting reactions to this stunning setback, Einstein offered an entirely fresh kind of hope through his unique, out-of-the box approach to scientific discovery, and the astonishing results it produced.

Moreover, and perhaps healing most the deeply bruised post-war human psyche, Einstein made no apology for the fact that, to him, widely acknowledged as the most profound diviner of the hidden laws of the universe, a spiritual force lay at the foundation of it all. In a world hungering to hear this, he attained the status of a rock star.

He was no Freud, or Bertrand Russell or G.B. Shaw who emerged in this era with a snide contempt for religion and its precepts. But equally, he was no fundamentalist, no believer that the spirit animating the universe, which he did call God, answered individual prayers or petitions to bring victory to home teams.

“There is a sense of awe and transcendent order that he discovered through his scientific work,” Isaacson, who also wrote a biography of Ben Franklin, writes.

“I am not an atheist,” Einstein said. “The problem involved is too vast for our limited minds. We are in the position of a little child entering a huge library filled with books in many languages. The child knows someone must have written those books. It does not know how. It does not understand the languages in which they were written. The child dimly suspects a mysterious order in the arrangement of the books but doesn’t know what it is. That, it seems to me, is the attitude of even the most intelligent human being toward God.”

Einstein did not hesitate to flee Germany when the Nazis took over. He seldom practiced the rituals of his Judaism, but preferred “an attitude of humility corresponding to the weakness of our intellectual understanding of nature and of our own being.”

Later in life, he assailed prevailing assumptions of the very science of quantum mechanics he helped create. It attributed the universe to “uncertainties and probabilities,” or, mere chance. No, he insisted. Instead, “there is a harmonious reality underlying the laws of the universe. It is the goal of science to discover it.”

Einstein’s nonconformist personality and rebellious instincts included his antipathy toward all war (except when it came to fighting Hitler) and intolerance. “Imagination is more important than knowledge,” he intoned. To him, the foundation of morality was “rising above the merely personal to live in a way that benefits humanity.”