High Quality Content by WIKIPEDIA articles! calibre is free and open source e-book computer software that organizes, saves and manages e-books, supporting a variety of formats. It also supports e-book syncing with a variety of popular e-book readers and will, within DRM restrictions, convert e-books between differing formats. There is built in reader for some formats while the remainder can be read by invoking the associated reader. calibre is cross-platform (programmed in Python and C) and is intended for the three main operating systems, Linux, Mac OS X and Windows. Since version 0.7.53 calibre supports extensions via plug-in components, each of which is a .zip file containing python code, text files and optionally image files. calibre was originally called libprs500, but was renamed calibre (lower case `C`) in mid-2008.