Having a background in science, with this book I felt the way I used to feel with college textbooks back in my student days - you're happy if you can digest a page or two in a day. But once you understood the stuff, the knowledge becomes a part of your internal thinking and reasoning.
Chapter 10 with its ad-hoc monadic parser is ``a newbie killer''. The discussions of parseByte on the website with the text of the book helps. Reading on the state monad helps to understand the chapter too.