Nice! Thanks for posting the scans/photos.
Old chess book
So that's what Horowitz looks like. I don't remember ever seeing a picture of him. I used one of his books extensively years ago when I was learning various openings. I'm sure the people over at the Chess Books & Equipment forum would like to take a look. They may even have some information about it.
@Gomer_Pyle, here are some better photos of Horowitz (as well as a few things about him). In the 1972 tournament Horowitz was already in ill health and would die shortly after.
https://www.chess.com/article/view/the-player-i-d-most-like-to-have-met
or
https://www.chess.com/article/view/the-golden-age
Horowitz vs. Kavalek is the first game in this book. Horowitz attempts to set up a mating attack on move 10, against the grandmaster. If he was sick, he was still a fighter, nevertheless. According to the note at move 15, they got the position,

Here, Kavalek played 15...Rae8 Then Horowitz played 16.Nd5?? and walked away from the board & said to a scorekeeper “Not bad for a patzer!” - the note says “White thinks the rest is taking candy from a baby...but taking candy from a baby requires that you first find a baby. Kavalek is an experienced grandmaster.”
Of course Kavalek slaughtered him and Horowitz resigned at move 26. But there’s a lot of anecdotes and witness accounts in this book and Hochberg writes his notes as if he were right there watching up close, commenting on all the emotions, and details of the players as they fought over the board. Apparently he was there, since he took the photos, but It’s like you can see everything, sometimes. Very good book!

Here’s an interesting book.