A Human Book is a person who has volunteered to challenge prejudice through respectful conversation with members of the public who "borrow" them to hear their story, in a 30 minute conversation. They will have a title that relates to their experience of prejudice, discrimination, or stigma.
When a question is too personal or private, you can say, "That chapter hasn't been written/published yet, but I'd like to hear your next question." or "Those pages haven't been written/published yet, but I'd like to hear your next question."