Each year our local chapter of the Red Cross has a used book sale as a fund raiser. It is quite the event with tens of thousands of books. We always attend and this year I found three books to bring home. My days of buying dozens of books are past.
I have long wanted to design a "Rescue the Romanovs" scenario. I hope there's some good information in the book I found. As for the other two, you can never have too many reference books.