This has been fixed as of patch 1.0.8x. The books are only sold once now.
Just started a fresh game with 1.0.8x patch and she is still restocking them for me.
This is great news for me! I've rerolled again. I simply cannot build the character I want to be my lead without those books.
My idea of a perfect lead character is always a sneaky rogue/mage. In this game however, with secret finding being necessary, perception should be on whichever character you plan to have selected when exploring. This character should also be the one that loots and identifies to keep inventory management to a minimum. So I need 8 INT, 15 base DEX, 8 - 10 PER (I'm guessing) and for AP I need SPD or CON (with glasscannon).
Basically the character has four attributes that need investment and without books is impossible to build well enough.