Maybe its the result of a lifetime of doing book-based research, but I find I can often get more information easier and faster in a catalogue than an online search. So I keep, and use the West, Defender, Jamestown ,Hamilton Marine, and Harken catalogues. One observation: With the advent of computer based indexing and cataloging, indexes in general have gone downhill. Developing a good index is both an art and a science, as I found out when my publisher kept returning the draft index for my first book.

Catalogues provide context, that their online equivalents don't.