Active reading (in contrast to passive reading) is when the reader fully engages, and learns from any text at hand in a book. The reader may mark up the book with meaningful symbols, make notes between the margin, highlight words, underline good dialogue examples or intriguing sentence structures, analyze use of story structure, leave commentary on things that they enjoyed in how an author phrased one thing or another---and so forth and so on. Essentially, they are "studying" the book as they read it, instead of just mindlessly consuming it, and moving on to the next gratifying story. I desperately want to do this with various books, especially fictional ones--in order to intimately inspect certain writing traits from my favorite writers. My question is, is it possible to practice active reading with digital books (such as in PDF or eBook form, or heck, even online stories)? You can't "markup" a digital book the same you would do a physical one (i.e with a pen and highlighter). In that case, what should I do--or are there any methods or programs I should be using to assist in achieving this?