Only some of them. For example, a few years I went through a period of reading all the fiction I could find by Isaac Asimov, and then Heinlein. I distinctly remember the plot of Asimov’s Nightfall and some of the scenes. I remember a select few plots and scenes from some of the many short stories, but can’t reliably recall even which of those two authors they were from, let alone which story or book. Others are just dust in the wind.

I have a very good memory for many things, but a book plot just isn’t something my mind has felt is necessary to retain. Like another poster said, I read for the escape, not as a learning experience.