What are the elder scrolls in the Elder Scrolls games

The Elder Scrolls themselves are prophetic writings of unknown origin. Those who can read the scrolls, will see visions about events past and future, though the future events are not necessarily certain - another seer may see another possible future, the true one is not known until the event comes to pass.

Reading the scroll increases the reader's skill in understanding the scroll, but causes temporary blindness. This blindness becomes permanent after multiple readings - ironically just as the reader gains a near perfect understanding of the scroll, he is stripped of his ability to read it.