I have found a Original Copy of The Raven I need help on determining value and what to do.?

Okay i have a book that i have just inherited recently. My grandfather just ped away recently and i whent up there with my mom to see the books. Well i picked out alot but my grandmother knew i was a fan of Edgar Allen Poe. Well my great great great great grandfather was a friend of EAP and was the Editor for the book The American Reveiw. In this book was the VERY first publicashing of The Raven. It has notes from G.H Colton. Who i am related to and was apparently friends with Eap. I need help on determining value and if i should go to the libary of congress to get this book looked out.