Spot those valuable books before the dealers do! If it's not for sale on any of these, you might have something really special - try just googling it. Appearances can be deceptive - a book doesn't have to look old, or even be hardback, to be scarce. Before being overwhelmed by the adrenalin rush that all bibliophiles live for, remember it's most valuable if it has a dust jacket, and is 1st edition, 1st printing. Value drops if the book has marks (eg "Roger's Book", scrawled in felt tip on the end paper), marginalia or book plates, unless it can be proved that "Roger" is someone famous, the marginalia are by Bertrand Russell, or the "Elizabeth David" book plate is in fact the Elizabeth David (did she go in for book plates?)
There are dozens of sexy ways to display books these days, so try to avoid late night sessions on the Gresswell library supplies web site after alcohol - it can work out v expensive. Anyway, you have been warned, here it is.
Can't have masked booksellers without masks!