One of the new Mythic Items in the High Isle Chapter is Mora's Whispers, and it gives you extra ciritical chance, inspiration, alliance rank progress and monster kill experience. However, the bonus scales up based on how many books you have collected from Shalidor's Library.
It's not made too clear exactly what Shalidor's Library is or where to find it, so this guide is intended as a simple explanation of what exactly Shalidor's Library is, and how you can find the books needed to complete it and get the most out of the Mora's Whispers mythic item in the Elder Scrolls Online.