1 Bitter, 2 Sweet

This story begins as eleven-year-old Severus Snape goes to Hogwarts. It features Severus, Minerva, Lily, Eileen, a couple of Malfoys, various Hogwarts staff (human and elf), portraits, and students. Plus a sentient book. What does one do with a sentient book? Why, turn it into a diary, of course.