I can never retain what I read by myself unless I have an audiobook or someone reading to me, but having just an audiobook isn't enough as the words would just go straight through one ear and out the other.
I need an ebook (or physical book) along with an audiobook to really enjoy the reading.
What the fuck is wrong with me? Am I retarded?
Thank God for LoyalBooks.
Make notes. Adjust your lifestyle, you could be killing your attention span by the means of internet, TV, vidya, <insert any other dopamine related activity that's not sport or sex>.
Write about the books you read. I like to look at essay prompts and run through a couple books for each book. Writing should your mind form more connections to and between the works you read.
I don't know how effective it is but it works for me
When you finish a chapter (or whatever), close the book. Now visualise what you have read. Go through the text in your mind. It's like clicking a photo and keeping it for posterity.
If you feel like, writing down a summary, that works too.
Off topic: Have you read Nicholas Carr's The Shallows? You are not alone in having weak retention powers. Technology shapes and molds our behaviour. Internet isn't suited for deep reading.