Librams are ancient keepsakes that are left of the Highborne legacy. Those codex are filled with indecipherable and skittering runes that can only be read by very few lore masters in the world. At this time there are only two such known - Mathredis Firestar, a recluse and crankly elf that resides in the Burning Steppes, and Lorekeeper Lydros from the secret archives of Shen'dralar in Dire Maul.
Librams can be turned in to one of those NPCs (each one only accept some librams), along with some other ingredients for an Arcanum, a gem that allows you to apply an enchant to a Head or Leg item. Only one libram of each type can be carried at a time, though the quests can be repeated any number of times.
Note that the quests do not generate experience, reputation or achievement gains. Nor can the resulting arcanum be applied to any but your own, Level 50+, head or leg item (see patch notes). However, a level 50-60ish character can buy the libram and any Blasted Lands items from the Auction House, and should be capable of running Blackrock Depths and Felwood for the other items.
Arcanum
Other than a few quests in the area, turn-ins of these Librams are the only way to generate reputation with the Shen'dralar.
See also
See also: Augments for further details on the enchants provided.