“Shalidor's Insights” is a Winterhold College Quest in The Elder Scrolls V: Skyrim
Head into the the Arcanaeum inside the College of Winterhold. Approach and talk with Urag gro-Shub. As him if he is looking for anything in special. he will tell you that he is looking for the writings of the Archmage Shalidor. He wants to translate them. The book will be found in any dungeon with a boss inside it. This quest is unrestricted and can bring you to a new location.
The dungeons include those added with the Dragonborn and Dawnguard DLC, even if you have not visited either area. If your quest marker does not show in Skyrim, then you likely need to head to either of the DLC locations.
3 Identical "Shalidor's Insight Scrolls" or a Magic Skill Book