I will list the rest according to my preferences for finding books on the net. The number one website bar none is AbeBooks.
Quite simply they have the most books the most dealers. Not to mention the best choice. Its a great pity that the people that started it didn't
stay on board but moved on their job being done. Everyone that uses Abebooks should thank Rick and Vivian Pura and Keith and Cathy Waters
Click the link above to read about them. After they left Abe went through many superficial changes, but nothing that improved what was there already.
They sort of bobbed around without a any real idea of the direction they needed to go. But Amazon knew what to do and did it buying them out. now Amazon
now had the best book site on the net, good one Jeff.
Next we have Biblio they maybe small but they are similar ideals to the original Abe team at the very least they deserve a chance.
I intend to make this my site of choice from now on, see you there.
Also a very good site in that it lets you look at a lot of other book selling sites BookFinder.
Then you can try Ebay as a last resort. After this you can spend many hours looking but really from this point it's just luck. Of which I wish you well.
After this you have Amazon or Bookfinder4U maybe Biblion you can try TomFolio
Finding used books in out of the way places If all this seems to hard then give us a call were only to happy to look & find that book for you.