I Have Made Many Posts,

about old books,

I have a few myself, these are some of them, most I have never given more than a few pounds for, 

but here is a small point, if you have what you perceive to be a rare book,

how much is it worth?

the answer to that lies with a company that has a guide to apprising rare books,

just pop over to the Biblio books web page which lists a number of pointers to its worth, also there is a form you can fill in with your books details, to see if any ones like yours are in the market place, and you can then see the price they sell for, but remember from the the store,

'A professional bookseller can give you an immediate fair offer for your book, but their price will need to factor in the profit they need to run their business, so don't be surprised to be offered 1/4 of the average retail. Their offer will figure in their costs and the time that they expect to have it in their stock before a buyer comes along', 

so you may want to find a private buyer yourself or perhaps put it into an auction, but first the difficult bit, find a rare book!