The Adventures of K9
The Adventures of K9 was a series of four illustrated paperback storybooks for children written by David Martin and published by Sparrow Books in 1980. The four books feature K9, the character Martin co-created.
Specifically, the stories (according to the Discontinuity Guide website) feature K9 Mark I and are supposed to take place sometime after the events of DW: The Invasion of Time when the Doctor left K9 on Gallifrey.[1]
The books include prefaces that indicate that K9 is working on behalf of the Time Lords (which opens the possibility that this could also be K9 Mark II, depicted in many spin-off media as eventually returning to Gallifrey with Romana who becomes Lord President.
A total of four books were published:
Although the general spelling used for the name K9 is hyphenated, these books consistently use the unhyphenated form, K9. They also suggest that the Doctor's real name might be the Theta Sigma nickname heard in The Invasion of Time and DW: The Happiness Patrol.
