Educated Warrior
Read the final novel segment.

After completing the game for the first time you will be prompted to save your game, do so and then load this save. This will activate New Game+ near the beginning of the second part of NIER. After a cutscene and inbetween a boss battle you will be treated to several of Kain's dreams in the form of a novel. Read through, or simply skip through the segments and the trophy will unlock.