Americans are drawn to explore the hidden, inner lives of their political leaders; the more mysterious and complex the better.

A new biography Barack Obama: The Story, by David Maraniss, taps into that drive to get inside the heart, the mind and the soul of the man leading the nation, a quest fed partly by human curiosity — a wish to understand an interesting human being — and partly by a compulsion to obtain special insights into the political man.

The more we get the psychological makeup, the more we see the demons the man has had to wrestle, the better we think will understand why he acts a particular way, why he holds certain beliefs.

Obama’s history shaped him as the perennial “other” — he was a dark-skinned boy with a white mother, raised partly by white grandparents in Hawaii, then in Indonesia by an Indonesian stepfather and his mother. Later, as a young adult in California and New York, he tried to figure out who he was, confessing he “felt like an impostor.”

He gradually made a deliberate decision to adopt a black identity, but also to embrace a bit of every portion of his uncommonly wide-ranging background. “Caught without a class, a structure or tradition to support me, in a sense the choice to take a different path is made for me,” he wrote to his then-girlfriend Alex McNear, adding, “the only way to assuage my feelings of isolation are to absorb all the traditions [of all the] classes; make them mine, me theirs.”

Bit by bit we see evolve the man we see today, a little distant, charming but reserved, able to function in any setting with ease, but with the somewhat calculated stance of observer more than participant; a man who exudes the self-assurance of someone who believes he understands all sides better than anyone else could ever hope to do.

By studying these frequent analyses, blends of history and pop psychology, we feel close to figures who have, by a twist of history, become part of our lives and yet remain personally unknown and largely unknowable.

The quest to understand them is alluring and filled with fascinating clues.

Each American president, like every human being, carries within him a unique history. But, unlike the rest of us, each has conquered the pinnacle of power. The formula that produces an individual who reaches the White House remains a hidden secret, but one most surprising ingredient has emerged as a common element in a series of presidencies: alcohol. Or, more precisely, alcoholism.

In the background of all but one American president in the last 30 years, alcoholism has figured prominently, usually as the poisonous potion that helped destroy father-son bonds. Perhaps it worked by creating effort to replace those missing bonds, or maybe to impress the ghost of the absent father. Or maybe it was the product of strong maternal figures that helped raise confident young men who then grew up with the belief and the emotional strength to take the top job in the world’s most powerful nation.

Obama’s father, Barack Obama Sr., the Kenyan student who traveled to Hawaii and met Stanley Ann Dunham, Obama’s mother, promptly disappeared from his son’s life and eventually destroyed his own, dying in a car crash in a haze of alcoholism.

Bill Clinton’s father, William Jefferson Blythe, also died after a crash three months before his son was born. The young Bill inherited his first and middle name, but took the last name of the man his mother later married, another alcoholic who abused Bill’s mother.

Ronald Reagan’s father, Jack, as his mother Nelled explained to him as a child, had a “sickness,” Reagan wrote, that’s “why my father sometimes disappeared.” That sickness was “an addiction to alcohol.”

Coincidence? Three out of the last five presidents had alcoholic fathers.

In the case of George W. Bush, it was his own history of alcohol abuse that played a role in shaping the course of his life, which pop psychologists saw as a Shakespearean drama, or perhaps a modern case of Oedipal rivalry.

By this time four years ago, we already knew much more about Barack Obama than we know today about Mitt Romney. It’s a safe bet the psychoanalysis will start pouring in, helping us make sense of the successful Mormon businessman who wants to become president; the hidden history awaits, the more mysterious and complicated, the better.