As recounted at the beginning of chapter 7, at Will's old prep school, prefects were known as 'librarians', the designation often taking a prefix to indicate the particular prefect's area of responsibility. Will, a keen swimmer at school as afterwards, became the 'Swimming-Pool Librarian'. His father, writing to offer congratulation, amusedly comments, 'you must tell me what kind of books they have in the Swimming-Pool Library.' For Will, the Swimming-Pool Library is slang for the changing-room to which he and his friends would slip in the middle of the night for illicit sexual activities.