Bookseller's catalogues are pretty much an extinct media, at least in print form. I have, over the last few months happened upon a few caches of them at auction or private sale and, as a result, I now have some six or seven hundred of the things, of all ages, on all subjects and from any number of different booksellers both modest and grand. Every once in a while I shall be posting images from this collection (and please do enquire if you would like to buy anything you see in these posts) because, to me, they are a fascinating thing, both for their contents and for the place they have as 'book ephemera' in the history of book selling.
Nowadays, go into almost any bookshop in the country and you will see the proprietor staring at a computer screen cataloging books. But it won't be on a word processor with a view to sending the text to a printers, it will be straight into the cataloging software of Abebooks. There are still, booksellers being a naturally old-fashioned breed, those who do produce printed catalogues but often this is done as much for the sales of the catalogue itself as for the sales of its contents, even these booksellers would much prefer to send you the pdf version of their print catalogue. Of course, the greatest resource these catalogues provide is bibliographical, whether that be from the descriptions and facsimiles of the first edition of Milton's Paradise Lost in the Henry Sotheran catalogue (@ £200 in 1907), or any one of the over 14,000 entries in Larry Edwards 1970s catalogue for the Cinema Bookshop, either way, to a collector, the right old book catalogues can be an invaluable resource.