The Librarian of Congress oversees the vast research resource that is the Library of Congress, appoints the US Poet Laureate and plays an important policy role on issues such as copyright.
Along the way, it may be possible they can also make history.
On Wednesday, President Barack Obama revealed he was nominating a candidate who, if confirmed, would be both the first woman and the first African American to hold the post in the library's 214-year history.
Mr Obama said the nomination of Carla Hayden, who has for many years served as the head of Baltimore's library system, would address a situation that was long overdue.
“I know she'll be a good steward for the important role that libraries play in our communities,” he said in a statement.
“Last year, during the unrest in Baltimore, Dr Hayden and the library’s staff kept the doors of the Pratt open as a beacon for the community.”
He added: “Finally, she'd be the first woman and the first African American to hold the position – both of which are long overdue."
Last year, Mr Obama signed a law establishing a 10-year term for the Librarian of Congress with an option for reappointment. The position was previously considered a lifetime appointment.
The bill was passed amid criticism of the previous librarian, James Billington, for not keeping up with advances in technology. Mr Billington was appointed by President Ronald Reagan and served for 28 years before stepping down at the end of last year.
The Library of Congress is the nation's oldest federal cultural institution. The Associated Press said it was formed largely based on Thomas Jefferson's collection of books to begin building a national library.
Its collection of 162m items includes research materials, historical resources and cultural treasures. The library also operates as a nonpartisan research organisation for Congress and runs the nation's Copyright Office.
Ms Hayden, 63 would be just the third professional librarian to serve in the position. The American Library Association urged the president to nominate a librarian, and Maryland’s two Democratic senators, Barbara Mikulski and Ben Cardin, recommended Ms Hayden last year.
“The President could not have made a better choice," Sari Feldman, the president of the library association, said in a statement.
Established in 1886, the Pratt library is the nation's oldest public library system. During the civil unrest in Baltimore last spring that followed the death of Freddie Gray from an injury he suffered in police custody, Ms Hayden kept the city’s libraries open, among them one that was located close to the scene of rioting.
“It became that community meeting place, and people were so relieved to have a safe place to be,” Ms Hayden said in a video released by the White House.
“Making those libraries vital to communities will always be something that I look back on and say, ‘We did that’.”