Big Finish CD booklets

Physical releases by Big Finish Productions often contained CD booklets with supplementary material to the audio story.

Liner notes
Booklets often contained liner notes from the writers, directors, or actors of a story. While originally untitled, these would eventually have standard titles such as "Writer's Notes", "Author's Note", "Actor's Notes", or "Director's Notes".

Instead of behind the scenes material, liner notes sometimes included fictional prose content:

Radio Times listings
From 1999 to 2002, Doctor Who-related Big Finish booklets had summaries of their audio story's episodes imitating the story listings which Radio Times produced for episodes of the original Doctor Who. These appeared in the booklets for the Main Range, Dalek Empire I, and the Excelis Saga.

Production Notes
Around 2003, the faux Radio Times documents in the Main Range were replaced with features imitating production documents of old Doctor Who serials. These would include production codes, recording dates, and the story's continuity placement with regards to prior Big Finish releases.

Who's Who?
Starting in 2004, releases in the Main Range included a Who's Who? feature with short biographies for a story's Doctors and companions, accompanied by listings of their first chronological appearances on TV and in Big Finish and illustrations of their faces.

Cast photos
From the first Big Finish releases in the Bernice Summerfield range, behind the scenes photos of the cast from the day of recording were including in the liner material. As the CD booklets eventually lessened in the 2010s due to the rise of digital distribution, behind the scenes cast photos were instead included on the Big Finish website.

Maps
Early Main Range cassette releases included maps of a central building from their story, including The Land of the Dead and Colditz.

Comics
The booklets for Dalek Empire I each contained a comic written by Nicholas Briggs and drawn by Tim Keable depicting a scene from the story. These were Invasion of the Daleks, The Human Factor, "Death to the Daleks!", and Project Infinity.

Illustrations
Starting in 2007 with Renaissance of the Daleks, some booklets contained digital illustrations.