Now I'm left wondering how well this would work substituting in different books.
Different religious texts? Especially if you pick one that is not part of the primary religion of the area you are located in.
A Modest Proposal? Probably the worst choice. Most won't recognize it and the few who do will assume satire in your response. (Also, essays aren't books, but who is counting.)
A certain book by Nabokov?
What about someone who seriously considers the question, but then says that they've read many books but don't really have one they consider the best? Too much of a non-answer?
Different religious texts? Especially if you pick one that is not part of the primary religion of the area you are located in.
A Modest Proposal? Probably the worst choice. Most won't recognize it and the few who do will assume satire in your response. (Also, essays aren't books, but who is counting.)
A certain book by Nabokov?
What about someone who seriously considers the question, but then says that they've read many books but don't really have one they consider the best? Too much of a non-answer?