I only know 3
1 in miraks temple
1 in the ruin you go to with neloth
1 in neloth house after you do a quest for him

I just cant seem to find the rest.

Main quest books are - Epistolary Acumen and Waking Dreams

Others

Filament and Filigree - Kolbjorn
The Hidden Twilight - Telvanni Tower / Staff Enchanter Room
The Shallow Regent - White Ridge Barrow
The Winds of Change - Raven Rock Mine
Untold Legends - Benkongerike

Wow so there are more than just 5 do you know the powers they give or at the very least what you chose.

Let me rack this old brain of mine. I rememer one you can choose from sorcery, or from warrior, or shadow. Another was choosing between a summoned butler to carry your stuff or a summoned merchant to sell your stuff to. Another had to do with shouts. i do not remember the rest. But it is all good stuff.

The butler sounds useful

Very, but I chose the merchant so when in a dungeon, and I get overloaded, I can just summon him and sell some of my plunder. lol

Oh yea thanks for this info it has been really helpful