Paul has since written a prequel to Leviathan for the Companion Chronicles range.

The Companion Chronicles "talking books" are each narrated by one of the Doctor's companions and feature a second, guest-star voice along with music and sound effects.

Susan also appears, played by Ford, in the Companion Chronicles audio drama series from Big Finish.

This is a special two disc Companion Chronicles release.

This is the first Companion Chronicles to be narrated by a character who is not strictly considered a companion.

Bowermen had played uncredited parts in previous Companion Chronicles.

Since then, it has also made a couple of single-episode plays from its Companion Chronicles line available for exclusive download through Doctor Who Magazine.

Oliver Harper is the first ongoing companion created for the Companion Chronicles range.

Unlike most Companion Chronicles releases, this is, for the most part, a full cast audio story.

Unlike past Companion Chronicles, this story does not feature any narration.