Visitors browse the W.K. Kellogg Arabian Horse Library at the ribbon-cutting ceremony last November.
The collection includes papers from the original W.K. Kellogg Arabian Horse Ranch, periodicals, and foreign and domestic stud books.
Other materials include correspondence, newspaper clippings, blueprints and photographs of the original ranch.
It is the world's largest library collection relating to Arabian horses.
"It's my baby," confesses Katherine Staab, Arabian horse subject specialist who has been working on the collection for nine months.
"I am over-the-moon happy that we're finally opened and that students and researchers can use this material."
The library provides a permanent home for the Arabian horse collection, which has been moved from place to place over the years with no dedicated space large enough to hold the entire collection.
Staab, carefully turning the fragile pages of a 1729 book, says: "I need to be the protector of these items.
"I hope that in 100 years, someone who has my current position will be showing these same books to students."
Measures have been put in place to protect the library's valuable collection.
A buzzer from the inside opens the door to enter the library, but Staab makes it clear that its purpose is not to discourage casual visitors.
"The buzzer is just for security purposes because a lot of our material is one of a kind," she says. "Don't let it put you off - we want you here."
Other precautions for preserving the collection include a ban on pens - only pencils are allowed - and all bags must be left in the lockers provided just outside the entrance.
The legacy of Kellogg is still very much a part of the university.
In 1949, he deeded 813 acres of land, which included horse stables, the family home and other buildings, to California for education. Cal Poly Pomona, which now has 20,000 students, was built on the site.
More than 50 years later, his foundation provided a $US2 million grant for the new library facility.