The first sentence caught my eye because I have this problem too:
Five years ago I realized that I remembered almost nothing about most books that I read.
Robert Heaton goes on to describe how began taking notes and writing summaries to help him remember what he reads.
It all sounded like a lot of work for pleasure reading, so I wrote it off at first, but the promise of remembering more of what I read is too enticing. So, I've started highlighting as I read my current book (The Prodigal Tongue by Lynne Murphy), something I never do. I'm highlighting bits that sum up each section, as well as details I find interesting. Thinking of writing a blog post about it when I'm done. We'll see.