Categories and monthly archives display the correct number of posts for a category or month in the sidebar; category and archive pages are associated with expected permalinks when they are selected, but, each categorical and monthly archive is only populated by my most recent posts, by date, in descending order.
I'm fairly sure the problem is in a theme file as I had this issue out of the box with my theme (although archive.php seems to be in order).
WP and all plugins are up to date. I've validated my markup; updated WP tags in theme files that have changed since 2.2; re-installed WP; deactivated/reactivated all plugins; deleted, reposted all entries; deleted and re-added all categories.
Any other ideas will be a help.
Sorry I'm unable to publish my site's URI publicly, but I am happy to post any code people might be interested in seeing into a paste-bin.