I Can't Believe I Missed This

It was not in my collection back in the 1960s, and although I am a Batman fanatic, I somehow missed reading this story even when I got the issue:

But it ends up being an amazing issue for me.  For starters, there is a Riddler clue:

That one might not be obvious to you, but it is to me, because it refers to my birthday: March 4th (March Forth!)  But it does not end up being a Riddler story, or a Getaway Genius story as implied by the cover.  In fact it is the final Outsider story:

I talked about the Outsider series years ago; I honestly thought I had read them all.  I am a little chagrined to find out that there was another tale.