Currently people can review release groups, events, and places. We'd like to expand that list by allowing people to publish reviews for books. Metadata about books can be retrieved from the BookBrainz project (by accessing the web API or its database directly). This project would require (1) extension of CritiqueBrainz back-end to support book reviews, and (2) changes to the web interface.

Also see: https://chatlogs.metabrainz.org/brainzbot/musicbrainz/msg/3798002/