"Sixth and seventh year." He said. "The library was my escape, the place I went to when the vanishing cabinet mission or the Carrows got too much. It started as a way to sneak books out of the library to take up to the Room of Hidden Things, but it took on a life of its own. After a while, building it just made me think of you, especially in seventh year. Half of what I knew about you was that you lived part-time in books. I knew that wherever you were, you were probably hating the lack of access to a proper selection. I thought maybe I could finish it and get it to you anonymously, somehow." He shrugged.