In a recent announcement, search giant Google said that it has added the 'increased portability' element to its colossal supply of public domain books, by offering downloads in the EPUB electronic book standard, or the open standard format.

Adding that it intends releasing over one million books in the EPUB format, Google reiterated that the EPUB is supported by a number of applications and is compatible with several devices - like the Android handsets, iPhone, as well as e-readers from Sony and Plastic Logic. As such, the downloaded public domain books from Google Books can easily be read on devices that support the format.

Elaborating on the significance of the EPUB format - which, incidentally the popular e-reader, Amazon's Kindle, lacks - Google product manager, Brandon Badger said that with an increasing number of people using new reading devices to access digital books, the main problem they face is that most devices have smaller screens that do not readily provide image-based PDF versions of the Google-scanned books.

About the EPUB format, Badger said: "EPUB is a lightweight text-based digital book format that allows the text to automatically conform or "reflow" to these smaller screens. And because EPUB is a free, open standard supported by a growing ecosystem of digital reading devices, works you download from Google Books as EPUBs won't be tied to or locked into a particular device."