Zuckerman's identity is first revealed to the readers in this moment. This is also the first encounter between Zuckerman and the Swede in decades.
I was wrong. (1.49)
Zuckerman meets the Swede to find out something juicy, interesting, and tragic. It's right there under his nose, but he doesn't see it. He has no idea about Merry, even though he later thinks the Swede thought that he knew all about it.
He wants something recorded. (1.74)
Zuckerman isn't just out to poke around in the Swede's head for fiction-worthy gems, but also to make a record of something that could be important. We can see this side of Zuckerman in all the careful details of the times and the places where the action plays out.
"Who are you, Socrates? I don't buy it. Purely the writer. The single-minded writer. Nothing more." (3.236)
If Jerry knew that Zuckerman was "impotent and incontinent" after prostate surgery, Zuckerman's purity might be easier to grasp.
"Writing turns you into someone who's always wrong." (3.21)
If you don't write anything, you can't write something untrue. But, as soon as you write something down, it's going to be wrong to someone, somewhere, on some level. That's all Zuckerman is trying to say.
"Christ, you even gave him a mistress. Perfectly misjudged, Zuck. Absolutely off." (3.79)
Zuckerman wants to make really sure we understand that he understands that he's writing fiction, and that since he never even talked to the Swede about any of this stuff, it can't be right. At the same time, he's hoping to capture some of the emotions the Swede likely felt.
"I found them in Deal, New Jersey, at the seaside cottage, the summer his daughter was eleven." (3.123)
This is the beginning of the end of Zuckerman in this novel. A few more smarty-pants comments and then he fades out of the scene and lets the Swede take over.