MarciusVetrack wrote: »

at what time the eiidetic memory lorebooks from imperial city resets form the bookshelves?

The short answer: next maintenance.

The long answer: books in an instance are generated when that instance is created. Private temporary instances (e.g., group dungeons, arenas, and trials) will have bookshelves reset every time the instance is reset.

Public temporary instances (e.g., delves, public dungeons, outlaws refuges) will reset when they've been vacant long enough to close down, in which case the next time someone uses them, they'll get a new instance. Depending on how popular such a location is, there might be enough people visiting it that it might be kept open for a very long time. (But if it's too popular, then you'll get multiple instances of that delve that gets created, each with its own set of bookshelves.)

Similarly, popular zones that have multiple instances to handle the large population will have different bookshelves in each instance, and you can try leaving and re-entering the zone to try to get into a different instance of that zone. Otherwise, for zones with fewer people, there's probably just one instance of that zone and its bookshelves will be reset when the server goes down for maintenance.

Which brings us to IC and Cyrodiil. Each IC/Cyro campaign is a single long-lived instance that persists from when the server boots up to when the server goes down for maintenance. There are two different IC instances for the two different campaigns, with different bookshelves in each, but each of these instances will remain stable until maintenance.