Your desire to explore subjects through the catalogue is something I understand well. I have often wanted the option to navigate from broad (History) to get more specific (Regional -> UK -> 20th Century etc). If implemented well, faceted search which I described in an earlier post could address this need.

By the by, librarians and software developers need this kind of feedback to design the best services for our users, so keep the ideas coming.

One feature I would like every catalogue to have is a guided browse function. Not every work that mentions the subjects of my PHD research falls directly under the relevant subject headings in the catalogue so it would be nice for library catalogues to facilitate guided browsing of broader subjects to enable users to work from broad categories to more specific ones. (A little like how amazon.com allows users to start at a wide category of books like “biography” and then search specific categories within this topic.)

This catalogue series is well done. Keep up the good work!