Here are all the different librams you can collect remember you can only have 1 book of the same type at once. Once you convert the book in the quest you can(theoretically) carry the same arcanum with you. The two letter abbreviations are BS and DM are for where the quest turn in is for that libram. BS = Burning Steppes DM = Dire Maul

What each of the arcanum do:

Rumination  - BS - 150 mana 
Constitution - BS - 100 hp   
Tenacity    - BS - 125 armor
Resilience  - BS - +20 fire resistance
Voracity    - BS - +8 str/agi/sta/int/spi (only 1 stat of the 5)

Rapidity    - DM - +1% haste to attacks (ranged/melee)
Focus        - DM - +8 healing and damage from spells
Protection  - DM - +1% to dodge

Arcanum you get as reward when turning book to particular NPC - with some additional material including 30G - so be ready, its expensive and material is also hard to get (soulbound as well, so you cannot buy some of it).

NPC in Burning Steppes (BS) is easy to access, he is by cave in north. Dire Maul Library is easy to access too - either you can go there when in party (from DM west or DM North), or you can go there alone via DM North (key needed of course). Anybody interested to know how, contact me in-game.