But one man struggled with that same task for more than a decade. His name is Edmund Morris, a Pulitzer Prize-winning historian chosen by the Reagan family to write the then-president's official biography.
Morris spent years watching, studying and talking to the president. He had unprecedented access to everything that went on in the Reagan White House.
But even with all that work and study, Morris found it very hard to define and describe Ronald Wilson Reagan.
When Morris' controversial biography of Reagan, "Dutch," was first published in 1999, 60 Minutes Correspondent Lesley Stahl talked to him, and to President Reagan's son, Ron, about the very public man whose private thoughts were a mystery to many. 60 Minutes II revisits those conversations.
The Reagans chose Edmund Morris to write the authorized biography of the president in 1984. He became a regular visitor at the White House at the start of Reagan's second term.
Morris enjoyed extraordinary access to meetings the president had with his staff, members of the Cabinet and Congress. Reagan's official biographer just stood in a corner and took notes.
"Reagan couldn't care less. He was so secure with himself," recalls Morris.
Did Reagan bare himself to Morris? Was he revealing? "Ronald Reagan was never revealing," says Morris, who slowly and steadily collected his perceptions about Reagan on thousands of file cards, "yards of cards."
After years of observation and research, of weighing and organizing facts and anecdotes, one section of his file cards continued to grow. It was labeled "inscrutable" and, according to Morris, it was a very large section.
"He was truly one of the strangest men who's ever lived," says Morris. "Nobody around him understood him. I, every person I interviewed, almost without exception, eventually would say, 'You know, I could never really figure him out.'"
Stahl talked with Ron Prescott Reagan, the younger of Nancy and Ronald Reagan's two children, shortly after Morris' biography of his father was published in 1999.
"He was a great dad for a very small child," says Ron Reagan about his father. "He was a very physical person, so he loved nothing better than to sneak out and, you know, play hooky from whatever he was doing, and go out and play football with the neighborhood kids or something like that."
"And the bonding that happened there was a significant one, I think," adds Reagan. "But it's telling that it happened in this sort of physical arena and not, you know, sitting down over a cup of coffee and talking about life."
Mr. Reagan's son tells Stahl he didn't know if there was a specific best memory of his father. "I think what has always impressed me the most about my father, as well as in a way being troubling about him, is that he treats everybody the same way," says Reagan.
"Now when you're his kid, of course, that doesn't always work for you. You want to be treated a little more special," adds Reagan. "But as you get older, you certainly do appreciate that he – well, in my life, I have never seen him condescend to anyone. I have never seen him belittle anyone. I have never heard him gossip about anyone or telling stories. He's a nice man to the core and a terribly dignified man. ...I think all his children loved him desperately."
Reagan says his father was "an example of courage and dignity. When you're faced with an ethical decision, perhaps, a decision of right or wrong, you could do worse than ask yourself what he might do."
Former President Reagan learned those values in a different era. And to understand that time, Stahl asked Morris to take 60 Minutes to the small midwestern town where Reagan was born: Tampico, Ill.
"His only ambition that I can discern in childhood, and in early adolescence, up till his college days, was to act," says Morris.
Morris says Reagan was convinced he had a happy childhood, despite the sobering discovery young Ronnie made one night after his family moved to Dixon, Ill. There, he found a man lying spread-eagle in the snow.
"It's his father, dead drunk," says Morris. "He never realized until that moment that his father was a fall-down drunk. So Ronnie had to literally pick him up by his lapels, smelling alcohol on his breath ... and carry the big man inside. And in a sense, the child became the father of the man right then and there."
After studying and thinking about Ronald Reagan for 14 years, Morris has reached some conclusions about the former president.
"I think he was a great man and a great president," says Morris. "When he became president, we were full of self-doubts. The national spirit was at rock bottom. And overnight, there was this mysterious change in the national self-image. It was so quick that it can only be ascribed to him."
Throughout his career, political opponents, world leaders, and the press continually underestimated Reagan, as in 1983, when he was roundly criticized for calling the Soviet Union "the Evil Empire."
"A lot of Russians will tell you that when he used that language, that biblical language, 'the Evil Empire,' that was when they, for the first time, began to accept the fact that they were, indeed, an evil system," says Morris.
"Did he really understand what he understood? I can't tell you what happened in his heart and in his mind. But a man can't go through 77 years of life and prevail so constantly throughout his life. And all his jobs, everything that Reagan did, he somehow always came out on top."
"That's more than coincidence or good fortune," adds Morris. "There's a huge drive there, a huge, quiet momentum that drove him, and I think he was unstoppable."
After leaving the White House, Reagan had just a few years to enjoy his retirement. In November 1994, he wrote to the nation that he had Alzheimer's disease. The handwritten letter, now at the Reagan Presidential Library, was the "great communicator's" final statement to the American people.
"An utter, unblinking acceptance of what was happening to him," says Morris. "And what is most poignant of all is the fact that when he finished, 'I now begin the journey that will lead me into the summit – sunset of my life. I know that for America there will always be a bright dawn ahead. Thank you, my friends. May God always bless you.' After he was through with that, the decline was very rapid. It's like this was the final letting go, the final document."
"It's impossible for any human being not to be distressed by that," says Morris, who admits he was very upset. "A man of great gifts and huge achievements reverting to childhood, the final naiveté that descended on him."
"I think the single most shattering story I heard about him was the fact that a friend put a white ceramic model of the White House into this fish tank that he had in his office. And he took it home in his fist," adds Morris. "And when Nancy pried his fingers open and said, 'What's that, Ronnie?' And there's this little, wet White House in his hand. He said, 'I don't know, but I think it's something to do with me.'"
Did Morris ever figure Reagan out? "He's still a mystery to me," says Morris. "Still a mystery, and I think he always will be."