Get Calibre Office Application Software Free. The open source free e-book library management application which covers all aspects of library management, e-book syncing, e-book conversion, e-book viewing and e-book editing for the major e-book formats. It is easy to understand and the application is relatively lightweight. Calibre is a complete e-book library manager that lets you totally organize your collection. With help of it you can easily convert your books to multiple formats and then sync with all of your devices. Calibre also adds tags and comments for better searching. Calibre’s device drivers will support all of the top devices and e- readers.