epub The ePub format is one of the many open source eBook file formats available. Initially released in 2007, it succeeded the legacy Open eBook format. The format was first defined by the Open eBook forum, part of the international digital publishing forum. EPUB digital books and publications all have the associated .epub extension and can be opened and viewed on any compatible device, software application, smartphone, or dedicated reader. The format is capable of optimizing the resolution of digital publications to suite the resolution of the device being used, making it inherently a 'reflowable' format.
pdf The .pdf file format extension was developed by Adobe systems in 1993 as a means of presenting documents in a consistent manner across different platforms, hardware, operating systems, and applications. The format was not released as an open source document format until 2008, though minimal proprietary technologies still controlled by Adobe Systems exist in the format. Every .pdf document carries with it the necessary meta information required to properly reconstruct the text, fonts, and graphics used to produce the document. This ensures that documents will be viewed in exactly the same way the author intended regardless of the device used to open the document. From conception to date, Adobe Systems has continued to support the format adding features with every iteration of the standard including hardened algorithms for document encryption and privacy. Today, many freely available readers exist allowing you to open and view .pdf documents and create or convert other file formats such as .jpeg and .doc into .pdf documents.