High Quality Content by WIKIPEDIA articles! Calibre is a free and open source e-book management tool that allows one to organise, save and manage e-books, in and between a variety of formats. It also supports e-book syncing with a variety of popular e-book readers. Calibre is cross-platform (programmed in Python and C) and is intended for the three main operating systems, Linux, Mac OS X and Windows. Calibre goes through a rapid development cycle, and chooses to incrementally fix bugs and increase the number of features available. Its current version is 0.6.53. Calibre uses both Trac and Launchpad for bug management.