I've looked and looked and looked. I want to be able to take notes on a PDF. (Not actually change the PDF.) There are quite a few programs out there that will let me highlight and underline existing text. After that there are a couple of programs that will let me draw on the PDF (circles, lines, etc). There's one that will go so far as to allow freehand drawing even. But it seems none of them seem to allow the addition of text boxes. Tomorrow morning I'm going to a presentation (as a participant). They have provided a 28 page PDF of the slides. Instead of printing the slides and taking notes on them I would like to follow along with the presentation on my tablet and take notes on the PDF directly. I don't want to edit the text already there, I don't want my text to fall in line or in formatting with the document ... I just want to "take notes" on the PDF. Of course, I then want to save it for future reference. Is there anything out there I've missed? Developers ... help?