There are known issues with using our built-in ePub reader (use it in "Full Screen" mode) with various small form-factor devices (see Readers). People seem to be having a better experience with the reader when using Chrome. If you do have problems reading on-line with other browsers, the easiest solution might be to just download the ePub file for off-line reading - just be aware that your own ePub reader will format the file differently from our on-line reader.