Back in 1980, four books were published from K9 co-creator David Martin which continued the adventures of the Doctor's second best-friend, who was now undertaking missions on behalf of the Time Lords. All four books have now been released as an audio recording by Explore Multimedia, read by the original voice of K9 himself, John Leeson.
- K9 AND THE MISSING PLANET
An entire planet vanishes — a planet that was owned by Tellac Inc., a galactic company that turns whole worlds into mines and factories for their own profit. K9 is sent to find the missing planet. He finds instead a new universe and a very strange new breed of men...
- K9 AND THE BEASTS OF VEGA
Outside, the space ship was surrounded by hordes of evil beasts -- a mass of fangs, jaws and lashing tails. The shadowy monsters loom over the ship, attacking from all sides. Sounds of panic and screaming ring out everywhere. Only K9 keeps his usual calm.
- K9 AND THE TIME TRAP
The entire Seventh Fleet has disappeared. The Commander says it is impossible. K-9 says that is only because the human mind cannot understand it. At just under the speed of light, he takes off across the deep starless gulf between the galaxies on another dangerous mission. He uses a battlecruiser as his bait — but first he must find the trap...
- K9 AND THE ZETA RESCUE
There have been great explosions in the galaxy. There is danger that the whole galaxy will be blown apart. The situation is too dangerous for even the Time Lords to handle. And so they call K9 to their aid. It is he who must save their world.