In Eggtown, his choice of books is particularly suspect.
The book is “The Invention of Morel” by Adolfo Bioy Casares. Here’s a tiny bit of the NYBOOKS.com blurb:
“Jorge Luis Borges declared The Invention of Morel a masterpiece of plotting, comparable to The Turn of The Screw and Journey to the Center of the Earth.
Set on a mysterious island, Bioy’s novella is a story of suspense and
exploration, as well as a wonderfully unlikely romance, in which every
detail is at once crystal clear and deeply mysterious.”
Thanks to Olivia for the tip.