John Van Horne, 63, who has presided over the Library Company of Philadelphia during nearly three decades of unprecedented digital change, has announced he will retire in May 2014.
When Van Horne arrived in 1985, the Library Company, founded by Benjamin Franklin in 1731, had a Wang word processor. Soon, it acquired a fax machine that used thermal paper.
Now the library has created a rich and growing online environment.
"This library has been in continuous operation for 282 years," Van Horne said in a statement.
"I cannot imagine a more critical task than ensuring that scholars and the public are able to have access to these collections and the historical insights they make possible - and that they are preserved for future generations."