Filtered Browsing / Search

Allow users to browse books with many filters:

• one or more genres
• one or more tags
• one or more moods
• range of publish year
• average rating
• number of readers
• length
• publisher
• author
• probably other criteria I'm not
  thinking of

Add to that, multiple sorts. Ie, sort by publish year, then by avg rating, etc

Example:

I might want to browse for books that have the "Fantasy" and "Adventure" genres with both the "Dark" and "Tense" mood tags released after 2010.