How Can I Tell If a Book is Valuable?

Lounge
1

I’ve been collecting old books for a while, most are old hardback copies of Agatha Christies. I’m trying to declutter and I don’t want to throw away or sell too cheaply anything that might have some value to it. Since a lot of these older books don’t say “first edition” how can you tell???

2

Would this help? http://www.classiccrimefiction.com/christiebib.htm

3

Thanks, that should help with the Christies! :hug: