One of my best friend's parents moved out of their house today. They gave 17 boxes full of random books. I've found some very old books so far. There's also one on Eugenics from 1920. I just stumbled across the oldest one: Advanced Arithmetic by Wentworth 1898. It's in remarkable condition for its age. I want to find out its possible value and the value of the other old books. Have any ideas? Thanks.