When Do the Spellbooks Change at Ivory Tower

Somebody suggested they rotated every hour, anyone know when they change?

They don't. This person is a liar... and should stop spreading his filth. I opt for murder.

What is his name?

They don't, that's funny though.

They refrest every hour, the new interlude ones.

They respawn every hour, but the list is always the same ^^

rune / goddard has the sb's too

The ones at Rune and Goddard are sold in the stores, not dropped from mobs. This includes Invocation SB, which I got for my SE. I don't know if the same books are sold at IT.

Satyr elders drop Invocation SB, had it from them.

Satyr elders drop Invocation SB, had it from them.

Yes, but you can also buy the book from the npc. Same as celestial shield and aura flash, they also drop from mobs and can be bought in the store. Maybe NCSoft will remove the books from the store for the next expansion (i.e. when all the old-timers who cannot farm those mobs anymore have bought their books), it does not really make sense to have these books as drops when you can just go to IT or Rune or Goddard and buy them.

ah k, when does the list change? every week?

The list doesnt change. The SB are always the same.

ah k, when does the list change? every week?

As said, the list does not "change". It is just that the NPC only offers a handful of the new spellbooks (as opposed to an unlimited number of the old ones), and if those new ones are sold out, you have to wait an hour or two for him to restock.