Necromancer of Thay book has unique camp scenes. *Spoilers*

[Sardorim]

If you have a companion do the first reading of it (and passing every check), after getting the gem into it, and then later long rest you will get a cutscene of the book trying to get that character to kill everyone in camp.

For me it was Astarion reading the book and managing to shut it when my character confronted them. It was then awkward for both of us.

[jill.shirley]

Hahaha me too. His little "Hello!" and nervous wave made me laugh.

[Moonbane]

The book is MINE! The rewards from it and the Tharciate Codex is just too good to waste on an npc.