In a video announcing that his presidential library would be built in Chicago's South Side, President Obama discussed the personal importance of the city, saying he "became a man" when he moved to Chicago. (Barack Obama Foundation/YouTube)

President Obama has chosen the South Side of Chicago, neighboring the University of Chicago, as the site of his presidential library. Now he needs to decide what his library, and his post-presidential career, will be all about.

The easy part comes Tuesday when Chicago Mayor Rahm Emanuel and Martin Nesbitt, chairman of the Barack Obama Foundation, will make the formal announcement of Obama’s choice at a youth center named for the late Gary Comer, who grew up on Chicago’s South Side and founded the direct-mail firm Land’s End in 1963.

Obama’s choice ties his library to a top-notch university while also giving him the chance to reshape living conditions and education among people on the South Side, where the president and former Illinois senator was once a community organizer. The foundation said that it will be located in either Washington or Jackson Park near the university.

“With a library and a foundation on the South Side of Chicago, not only will we be able to encourage and effect change locally, but what we can also do is to attract the world to Chicago,” Obama said in a statement Tuesday morning. “All the strands of my life came together and I really became a man when I moved to Chicago. That’s where I was able to apply that early idealism to try to work in communities in public service. That’s where I met my wife. That’s where my children were born.”

Presidential library museum attendance in the past 40 years

The foundation said it will maintain a presence at the other sites that were finalists in the bidding for the Obama library: Columbia University, the state of Hawaii, and the University of Illinois at Chicago.

The heads of other presidential libraries note that Obama’s relatively young age could give him a chance to carve out an expansive new role once he’s out of office, and the library could serve as a platform.

“One of the things I think the Obama library foundation can learn from previous presidents’ libraries is that they are not just about the past but in cases of former presidents like Presidents Carter, Clinton or Obama, they’re about the future,” said James L. “Skip” Rutherford III, dean of the Clinton School of Public Affairs who for seven years oversaw the planning, construction and opening of the Clinton library in Little Rock.

“If you’re Obama,” he added, “you have a lot of life and a lot of time ahead of you.”

Rutherford said he has spoken to some people involved in the Obama library effort and has advised them to “remember to leave room for the future.” He said that when building presidential libraries, most people are “thinking about the moment.”

The presidential library boom began with Franklin D. Roosevelt, who in 1939 donated his personal and presidential papers to the federal government and pledged to donate part of his Hyde Park estate to house the documents, according to the National Archives.

Harry S. Truman followed suit, building a library in Independence, Mo., where he frequently used an office and where he occasionally welcomed tourists.

But Jimmy Carter “changed the mold because he was focused not on dealing as directly on his presidency but to use his clout to raise money . . . for very concrete accomplishments,” said Jay Hakes, who served as director of the Jimmy Carter Presidential Library and Museum for 13 years.

Carter has used his library as a base to fight disease and monitor dozens of elections in developing countries, Hakes noted.

Now Clinton has done something similar with the Clinton foundation, taking on global development issues.

Carter “was the one who said, ‘I’m going to focus on my post-presidency.’ Clinton followed that model,” Rutherford said. “Carter wrote the book. Clinton turned it into a set of encyclopedias. Obama? He is probably going to digitize it.”

Presidents tend to put their imprint on their presidential libraries.

The John F. Kennedy library, designed by I.M. Pei, resembles a sailboat.

The Lyndon B. Johnson library has a huge atrium, reflecting Johnson’s penchant for size and ambition. President Reagan and his wife, Nancy, wanted a western feel, so they chose a mission-style building on 100 acres of undeveloped land in California’s Simi Valley, where cowboy movies were once made. George W. Bush’s library is surrounded by native vegetation that his wife, Laura, suggested.

When setting up his center on the edge of Atlanta, Carter thought the designs submitted by big-name architects were too grandiose, Hakes said. After his success negotiating the Camp David accords that fostered peace between Egypt and Israel, Carter hoped to bring international leaders to Atlanta to negotiate. So he wanted his own Camp David-style institute. In the end, he did not host peace talks but turned to monitoring elections.

“Everybody tries to develop their own style,” said Hakes, who has visited every presidential library.

Clinton wanted to revitalize downtown Little Rock, Rutherford said. “He took an old warehouse district and completely transformed it,” he added.

Clinton was particular, Rutherford recalled. He wanted his library to have exact replicas of the Oval Office and Cabinet meeting room because, he said, so few children in Little Rock would ever travel to Washington — much less see the inside of the White House.

When the library was nearly done, Clinton walked into the duplicate Oval Office and said, “You don’t have this right.” The ceiling, he said, was too low. Someone fetched a tape measure and a step ladder and — sure enough — the ceiling was about 10 to 11 inches lower than the 18.5-foot ceiling in the real Oval Office. Rutherford had it torn out and redone.

Legislation in 1955 mandated privately financed and federally maintained libraries.

The Presidential Records Act of 1978 made presidential records the property of the U.S. government as soon as a president leaves office. In an effort to prevent costly libraries from draining money from taxpayers, a 1986 law established that the libraries must have private endowments whose size would be proportionate to the size of the libraries.

People who have served in leading roles for both Democratic and Republican former presidents say the Obama foundation will have to raise an endowment of about $500 million, in addition to the cost of construction. The foundation, which is an independent organization, said the University of Chicago has pledged to make resources and infrastructure available for planning and development work.

Presidents generally have refrained from raising money for their libraries while still in office, lest donors attempt to win favor with contributions.

White House spokesman Josh Earnest said Monday in a news briefing said that Obama will abide by a campaign pledge to follow standards of “disclosure and transparency.”

Earnest said that includes “not accepting donations while the president is in office from PACs or lobbyists.” He said he thinks the Obama foundation will disclose all donations exceeding $250.

In addition, Earnest said, the president and first lady Michelle Obama will not raise money for the foundation while Obama is still in office.

Although established originally by Roosevelt and Truman to house papers that might otherwise be scattered among different libraries, the modern presidential libraries serve educational and other purposes.

After a tsunami hit Japan in 2011, former president George H.W. Bush went to Little Rock to film an aid appeal with Clinton. Afterward, the two chatted in the faux Oval Office. Rutherford was standing outside the office when two tourists walked up. One said to the other, “Hazel, they’ve got a wax museum here,” he recalled.

A few moments later, Bush stood up to leave, walked over and said hello and shook the woman’s hand.

“Hello, I’m George Bush,” he said.

Stunned, she asked: “Are you for real?”After she walked away, Bush asked Rutherford what that was all about. Rutherford told him, “With all respect, she thought you were all wax figures.” Bush started laughing.