Librarian's Gift (achievement)
From Halopedia, the Halo wiki
Librarian's Gift
Librarian's Gift is an achievement in Halo: The Master Chief Collection. It is unlocked by completing the Halo 4 campaign on Easy difficulty; it will also be unlocked if the player completes the campaign on a higher difficulty. The achievement is worth 10 gamerpoints.
Trivia
The Master Chief Collection is the first Halo game with achievements specifically for completing campaigns on Easy.