Originally Posted by sun surfer
The range is so large in the MR Library. That's like asking what's your favourite book available at Barnes & Noble.
As you say. So the way I choose to interpret this question is: “What book available here is the best constructed (proofread and/or well formatted) and/or a wonderful book that only its presence in the MR library made one aware of?”
On this basis I would say Three Men in a Boat
and any of the books by Lord Dunsany.