Kindle Books are specifically formatted for use by the Amazon Kindle and Kindle apps. Please select this format if you wish to read the eBook on these devices.
EPUB eBooks have reflowable text, which means that if you resize the text or change the font of the eBook, the text will “reflow” to fill the screen.
PDF eBooks preserve the layout of complex documents, including any charts and illustrations. However, because of this they do not "reflow" their text as well as EPUB eBooks. Therefore, you may notice page breaks in odd places when reading these eBooks on an eReader device. Because they are not optimized for small screens, PDF eBooks cannot be downloaded using the OverDrive Media Console for mobile devices
Check OverDrive’s Device Resource Center to see what formats are compatible with your particular device. (Note that EPUB and PDF eBooks are not compatible with the Amazon Kindle.)