Wish you could see the "Library" in the tree.

I have kind of got used to using the convenient Library. Can that be set up?

I’ve liked the fact that all the pertinent folders can be found in one place, and have added more folders to my Library that I access often. Would be nice if we could customize the tree, to add a Library. Or, to arrange some folders to be listed together in one place.

Thanks in advance for any help or comments!