Originally Posted by EldRick
David Soulayrol is absolutely correct. The whole point of the PDF format is to allow the author/publisher, not the reader, to control the appearance of the document. It was designed to support typography properly. Think of it as a page sized image, designed to allow printers to duplicate the look of an original document.
I know that's the theory, but it really assumes you are displaying the PDF on the device at least equal, or larger than the target format of the PDF. Any attempt to display on a smaller device, like our ereaders, is quite awkward, and this is why the smart manufacturers have introduced reflow on PDFs.