2000 Year Diary

Deep in the library of the TARDIS, the Doctor keeps a record of his memories, just in case a future regeneration were to forget the past. That's what he does when his companions sleep, when he is alone in the TARDIS with nothing to do. He writes his memories into blue, leather bound journals and locks them away where only he can read them. Only him. And if he were to forget one day, hopefully he would find his way to the journals and have the curiosity to read them.