Librarian of Congress James H. Billington. (Douglas Graham/CQ Roll Call)

Librarian of Congress James H. Billington announced Friday that he will retire Sept. 30, three months earlier than scheduled.

In a letter to staff, Billington said the job that he has held for 28 years has been “the great honor and joy of my life” but that he will step down next week to “begin spending time on long-postponed writing projects and with my beloved family.”

Billington, 86, announced in June that he would retire at the end of the year. The 13th librarian of Congress, he was appointed by President Ronald Reagan in 1987.

Billington’s abrupt departure comes weeks after the library experienced widespread computer failures that shut down the U.S. Copyright Office’s online registration system for more than a week and interrupted some electronic services of the National Library for the Blind and Physically Handicapped.

In March, a congressional watchdog agency issued a scathing report about the technological problems at the Library of Congress that blamed the executive leadership for wasting millions of taxpayer dollars.

David Mao, the deputy librarian of Congress who has been part of the leadership team since January, will serve as acting librarian until a presidential appointment is made.

David Rubenstein, chairman of the library’s James Madison Council, praised Billington for launching the National Book Festival and other programs.

“Jim Billington is the Librarian of Congress, but in my view he is the Librarian of the United States. He has done a great service for our country,” Rubenstein said in a statement.

Founded in 1800, the Library of Congress is a $630 million operation with 3,200 employees that serves as the research arm of Congress, provides Congress legal advice and runs the Copyright Office, a major contributor to the world’s digital economy.