Today’s Saturday Stumper

Today’s Newsday Saturday Stumper, by Matthew Sewell, is quite stumperrific. A very difficult puzzle. I started out down the right side with some help from L. Frank Baum: 13-D, six letters, “Auntie Em, for instance.” And then some help from Thomas Hardy: 44-D, six letters, “Ruler from a tree.” The right half of the puzzle went pretty quickly. The left, much less so. And the bottom left corner probably took me as long as the rest of the puzzle.

I know: “Who cares?” I mean, I know who cares. That’s 35-D, three letters, “Who cares?” — one of several very clever clues.

My favorites:

25-D, eight letters, “Stop being square.”

37-A, eleven letters, “Online header of a sort.”

37-D, eight letters, “Booster unit.”

38-D, seven letters, “Occasional catcher.”

45-A, three letters, “Main menu openers.” Really, I hate this kind of clue, but I respect it.

59-A, four letters, “Release a crew.” Uncle!

No spoilers: the answers are in the comments.