Let's be honest; the best lore-related achievement is without question Loremaster, which requires you to do the vast majority of the game's quests. But that's pretty self-evident -- "To get the best lore experience in-game, do the quests, which contain virtually all of the actual lore!" -- and thus kind of a cop-out from my perspective. So what I'm going to do with this edition of OverAchiever is pointedly ignore the fact that Loremaster is the most important thing you should do as a dedicated lore junkie, and turn to some other options that tend to be overlooked.
As with our article on Twenty-Five Tabards, this is not an exhaustive guide on how to do each achievement, but simply a starting point if you're either interested in Azeroth's history, or interested in your character becoming more deeply involved in the developing story. As an early warning, 1 of the following 5 achievements is no longer doable, but I've decided to include it as I think the inability to do it at this point in time could be considered part of Azerothian history.