You can organize your collection by author, publication date or publisher, among others.
One of the most interesting features lets you convert between eBook formats, transform a newsfeed to an eBook or synchronize the eBooks with an external device.
It supports all kinds of formats, both reading and conversion, from the most popular ones like ePub, PDF, txt, or RTF to the export to fb2, OEB or MOBI.
Another one of its most valued features is the possibility to synchronize your books with your eBook reader, be it an Amazon Kindle or other models like Papyre, Cybook or the Sony PRS.
Calibre uses a Cover Flow style interface to navigate through the covers of the books. It also lets you edit its metadata from the interface of the program and explore the collection of eBooks from a web browser.