Calibre Library (paid), an app by Tony Maro that allows one to 'Connect wirelessly to your Calibre e-book library or other Stanza source.

Calibre Companion (paid), an app by MultiPie, Ltd., recommended by calibre's developers, 'brings complete integration with calibre on your desktop, giving you total control over book management on your device.' John Jermey at Teleread notes this app can manage Calibre/device libraries as if one's mobile device were plugged into computer however, unlike Calibre Cloud, Calibre Companion requires users to be at a computer and use the Calibre-generated local wireless feed (OPDS).

Because the Calibre-generated local wireless feed (OPDS) can only be accessed on devices sharing the same network as the Calibre library, this feature of the Calibre Cloud apps is particularly useful when away from one's home network, because it allows one to download and read the contents of one's Calibre library via the Calibre folder in Box, Dropbox, or Google Drive. As Jane Litte at Dear Author and John Jeremy at Teleread observe: This tool can be used to 'create own Cloud of eBooks' and thereby read and allow downloads and emails from one's Calibre library via the Calibre folder in Box.net, Dropbox, or Google Drive. Place your calibre library in your Dropbox, Box, or Google Drive folder, and be able to view, search, and download from your library anywhere'.

Calibre Cloud (free) and Calibre Cloud Pro (paid), apps by Intrepid Logic that let one 'access your Calibre e-book library from anywhere in the world.

Since version 1.15, released in December 2013, Calibre also contains an application to create and edit e-books directly, similar to the more full-featured Sigil application, but without the latter's WYSIWYG editing mode.

Calibre mac to nook