Prof Olssen, a leading New Zealand historian and former James Cook Research Fellow, said graduates faced "greater challenges" than when he graduated with an Otago degree nearly 50 years ago.
These included "navigating the tidal wave of expanding knowledge", he told more than 340 graduates in all academic disciplines at a Saturday graduation at the Regent Theatre, Dunedin.
"Where I thought I knew almost everything when I graduated, you know that you are merely equipped to start the adventure."
Reflecting on the "knowledge explosion", he noted 332,000 books had been published in 1960.
These had joined about 10 million books that had been published in Europe since Gutenburg had invented movable type.
In 2010, 2.2 million books had been published.
And that year, in the United States alone, about 2.7 million out-of-print titles became digitally available.
He reflected that when he graduated, the university had "some 3000 students and the city boasted one licensed restaurant and one dealer gallery".
"If you wanted olive oil you had to go to the chemist, wine you had to go to the Department of Agriculture's offices in the Post Office, and margarine was illegal."
His Otago history degree had focused on "the history of England's Home Counties" and New Zealand history could not be studied at any university.
He noted Otago's modern central library had been "the world's first fully successful post-library library, a smart building that even now is ahead of its time".
At the Otago campus in the late 1980s, dramatic growth in the student roll had made the university's previous main library, which had opened about 1965, "too small and antiquated".
Its inadequacy had been underlined by the "explosion of print" and the onset of the digital age.
He had been invited to help in planning and managing the new library project, which aimed to "integrate the digital with the traditional" and give students a refuge from their "cold flats".
Some people on the library working party had believed the book was "in its death throes" but this had proved to be far from the case.
During his undergraduate years, the university Clocktower building had housed an earlier library, which had been run by "fierce people" who policed "immutable laws" - neither to eat or drink and to speak only in whispers.
But in the Link area, beside the current library, students were "encouraged to eat, drink, talk, and read at the same time" if they wished.
