Aldebaran City -> South Left warp -> Inside the Alchemist Guild building, one of the NPCs there should sell you the books.
Nevermind.
It's located at Yuno, inside a building at 10 o' clock from the main plaza (big circled area) (for more visual aid, besides the WoE flags).
The NPC is called Pisruik, and you have to bring him certain items first so he can give you one of those books. And of course, you have to be an Alchemist/Biochemist so he can talk to you.
