The book itself is called Which lie did I Tell? And although this bit comes quite early in the text (I should disclose it's been a couple decades since I've read it), the book is mainly biographical.

Its a fun and smart read, but doesn't devote more than maybe a chapter reflecting on this revelation, even though Goldman, who wrote it in all caps in the book (which is why I wrote it that way in my post), considered it his most important or influential observation.