Just Joking (I hope)

Taylor,
I hope you were just joking about "permanently borrowing" the Sumpter Valley book. A number of years ago, Trains Magazine ran a back page commentary by the head librarian of the University of Michigan Libraries. They had been forced to stop the circulation of their railroad related books, due to theft. He reported that railroad books had the highest rate of theft of all categories. I guess this also fits with the railroads experiences with railfans as "railthieves." "Preserving" something by stealing it is not acceptable.
What is acceptable is buying it. Talk to your library. If their records support your assumption that no one is checking the book out, they may be willing to "deaccess" it to you. Libraries cull their collections all the time. Good luck.
Michael Allen