I've asked before whether such existed and was told no, and there appeared to be no plan or intention to add it. But now I'm asking specifically that it be added.
Here's a scenario where it's needed:
I've bought a ton of new books and am going through tagging them. I've got my Library sorted by Last Updated. The easiest way to tag large bunches of my new resources at a time is to group by author, since there are a number of resources by the same author, and that tells me something about the type of resources they are, or what bundle they were part of. So I'd like to be able to set the author as the secondary sort column. So far so good, but the problem is, I lose the face that all my most recently acquired books were at the top. Those were the ones I was working on tagging. Sure, there are a ton of other books in my library that I've never gotten around to tagging at all, so they have no ratings yet (one of my only ways of weeding out books that haven't been tagged yet, along with a few tag keywords I apply to most books after I've tagged them) and thus they show up in my current library filter.

So what I really need is a way to say show me only those books that I acquired on (date) or today or more recently than (date), and then sort/group them by author (or publisher, or whatever else I might choose as a secondary sort column).