Possible Clues:

• 'The Lord of the Rings,' notably
• Hear about one record in a series
• Bid to include single record in group of three
• Work in three parts
• 'The Hitchhiker's Guide to the Galaxy' five-part series, jokingly
• Triad
• Group of three literary works
• ''The Lord of the Rings,'' among others
• Aeschylus' 'Oresteia,' e.g.
• Series of three related works