Would You Like a Pamphlet?

During the quest Assault on Pillars of Fate/Assault on Pillars of Fate in Shadowmoon Valley, there will be little items called "Hidden Tome" that will grant a buff that lasts 5 minutes. They will randomly grant one of three buffs. You need all three to get the achievement. They spawn at various locations as mentioned by AkumaVentrue and NaThuRe:

/way 74.62 31.22
/way 74.27 27.73
/way 74.6 31.2
/way 72.76 32.50
/way 71.7 27.9
/way 70.51 24.15
/way 69.73 20.0

They have a respawn time of about 2 minutes; they pop-up fairly frequently. Just run around and open them until you get the three buffs.

Once the Assault on Pillars of Fate quest finished, I was no longer able to interact with the tomes so this can only be completed while the apexis daily quest is active.

One annoying problem with this: when I entered one of the huts, there is the third tome I need right in front of me... but (ahem) THE BACK OF THE HUT IS NOT CONSIDERED TO BE LOCATED IN THE PILLARS. This means that as soon as I get close to the book, the quest drops from being active and guess what? THE TWO BUFFS I ALREADY HAD DISAPPEARED TOO. robblerobblemouthfoamingrobblerage!

I decided that this was done on purpose by one of the few remaining sadists working at Blizz that slipped through the cracks. Then I stopped being lazy, watched a few more vids and found more spawn locatons. Problem solved.