Originally Posted by Mainewha
Asfar as I know it will unlock as soon as you have retrieved the last diary.(that's how it happened for me)
You were right, it does unlock just as soon as you grab the last journal. I wanted to make sure because the journal entitled "First Encounter" (I think) didn't show up like the rest had when I'd press start and go view the diaries. It put it in with another levels diaries, which after reading and reading around the forums... I finally discovered. But still... thanks. I got the achievement.