If your phone supports one of these file formats .doc .pdf, .txt, all you need is translate the source file into this format. Download the desired book from the Internet. As a rule, books are in the format .doc. To convert to .txt you will need to copy the entire text and paste it in a blank file created with Notepad. Note that for readability it is preferable to create multiple documents.
In case, if your smartphone supports the format .pdf, download and install the program Doc2Pdf, then use it for conversion. Copy the resulting files to the SD card of the phone or use the synchronization data cable.
If your smartfon supports java applications, you will need to convert a text document into a java application. In this case, you need to use a special BookReader app that is installed on your computer. Download and install this software. Then open with it the file you want and adjust the font size, background color and font based on your needs. Big font and grey background will allow less strain your eyes, while the white background and the small font will allow you to fit more characters on one page but will increase the burden on the eyes.
You can also use a special application which will allow you to read text documents directly on the smartphone. To do this, download and install it in the phone app, after which using date cable or through the memory card, copy to phone memory file with a text book. The easiest and most convenient will be, if these files are in format .txt, and text will not be in one large file and several files of small size. This will reduce the processing time of the file while reading, which will significantly simplify the process.