title_body: Reading PDFs on Kindle device I have many interesting books and documents in PDF format. Can I read PDFs on Kindle in comfortable way? 
  
  My concern is, that PDFs are adapted to the print page size and Kindle screen is much smaller. Would the PDF be readable?
upvoted_answer: It is possible, but will need prior processing for optimal results.
  
  You can use the free tool k2pdfopt to optimize PDFs for your reader's display size.
  
  It can handle up to four columns, works with "normal" (using actual stings in the PDF) as well as scanned text and will turn your input PDF into a PDF with more pages optimized for your screen's size. Newer versions of the program can even text. Text reflow preserves images and even mathematical formulas -- which is something that Sony's built-in text reflow cannot do.
  
  Download the program, set the options for your reader on a Windows/Mac/Linux machine and generate a new PDF with only one column, cropped margins and possibly larger letters. The conversion progress is largely automatic, just give it a try.
  
  If you do not mind jailbreaking your reader, there are also PDF viewers that include k2pdfopt and so you can change font size and other parameters on the fly. These also have the advantage that you can use the PDF's table of contents (something the official PDF viewer does not support). The readers are all forked from the same project and only differ in how you input your data. They are KOReader (for Kobos and Kindles with a touch screens), KindlePDFViewer (for Kindles with keyboard) and Librerator (for Kindles with neither touch nor keyboard).
  
  A clear disadvantage is that these programs seem to drain more battery than the official PDF viewer, but on the other hand reading is more convenient, because you can still read in portrait mode and your pages are preprocessed in the background (turning pages feels faster in large PDFs with many images). And battery life is still several weeks. 
  
  Other than this you can of course read in landscape mode. This can be quite annoying with multicolumn documents or if you want to go back just one page to look something up (may feel slow). It is fine for texts you read without going back and it's still the way to go e.g. if you have large tables in your document. I used it for text books as well for years, so it is not too annoying.
  
  Another option is converting the PDF to Mobi using Calibre or Amazon's mailing service. This will usually fail completely in multicolumn documents, will remove images and destroy mathematical formulas. It will also often lead to page numbers or chapter names (if it is written on top of every page) in between the text.