I normally read books on my kindle but this doesn't work for technical books with graphics and the need to go back/forth between pages. Normally when I know I won't be implementing anything I will use my iPad to read a PDF, but I've found that reading technical books without keeping notes isn't very useful. This means my laptop would be the best way to read and write down notes, but I would rather not sit at my desk even more than I already do.
My first stage is to start a file where I write my own guides/books as a reference. The subtopics here are things like a to-do list, questions list, project area, log, resources area. I try to get some pseudocode in the log or project area as soon as I can, for things like language learning. I find this is really fast for my own learning style, compared to starting with the books and particularly those using a linear teaching method.
Have you tried reclining or laying down with a laptop and possibly a laptop stand/desk? When I need to read books on the laptop I find this really comfortable. It took some experimentation to find my best setup though, like which lumbar support to use for which chair, when to use trackball vs. touchpad, etc.