Amazon, the world’s largest online retailer, has expanded its territory in the fast-developing world of digital books, with the acquisition of Lexcycle, whose Stanza e-book reading application claims over 1.5m global users.

Stanza has been the leading e-book reader application used by owners of Apple iPhone devices. The deal gives Amazon digital reading software that supports books formated according to the ePub standard, an open format endorsed by the International Digital Publishing Format.