The EPUB format has become established as an open standard for digital books. It is considered to be the successor of the older formats OEB and OEBPS. EPUB files can be viewed and read using readers such as the Amazon Kindle, Sony Reader or Tolino, etc. In addition, there are a lot of apps that are available for both Android and iOS. On Windows, maxOS and Linux you can use the open source program Calibre. With Calibre, you can also convert EPUBs to other formats, such as PDF or the MOBI format.