Soul Cairn - After passing the fortified wall (on the path to the castle) that separates areas, to the right there will be a ghost merchant named Morven Stroud, next to a broken horse carriage, the page is on a barrel next to Morven.
In some cases, the page is slightly clipped into the barrel, rendering it not visible and impossible to grab. Firing a Fireball spell at it or summoning a Flame Atronach and then killing it (causing it to explode on death) can sometimes make the page re-appear. It is unclear why this works, but seems to be a reliable fix for the problem.
about to strike me down in anger for my somewhat sordid past?
Suddenly I understood everything. Suddenly I realized that I was brought here for a reason. I should have died in those ash wastes, but Lord Vivec must have seen something inside me that he hadn't seen in millennia and decided to spare me from my fate.
Thus began my ascent to Sainthood. Thus began the rise of Jiub!