The Oracle of Time, earlier referred to as the Oracle of Infinity, was a guiding force and "patron saint" of the Spacing Guild.
Like Daniel and Marty, the Oracle of Time possessed apparently paranormal powers. For example, she once transported the no-ship Ithaca from an alternate universe back to the Old Imperium, and informed Duncan Idaho of his role in Kralizec, the so-called Final Battle. In another example, she called all Navigators to a certain coordinate, and when they arrived in their Guild ships she folded the fabric of space and collectively transported them to an uncharted universe where the Ithaca was located. Practiced the deus ex machina to a good extent.
Ultimately, it was revealed that the Oracle was the ancient consciousness of Norma Cenva, the first Navigator.