Lachdanan's Scroll
This item was found on the first level of the dungeon below Tristram, in the Blizzcon 2008 demo. When played, this one was a lengthy narration by Lachdanan, an NPC who was seen in Diablo I. Lachdanan was the leader of King Leoric's knights, and the man who finally killed the mad king, putting him out of his misery. Leoric cursed his followers as he died, and condemned them all to eternal damnation. Lachdanan alone survived this fate, when the hero found a special elixir for him on a quest in Diablo I.
Lachdanan's scroll in D3 basically retells his story from Diablo I, providing useful background information about King Leoric and the first major quest in D3. Not everyone playing the game will remember the quest events and story from the first game, after all.