Target novelisations exist for almost every Classic Who story ever (except maybe the ones by Douglas Adams.) Thanks to splendid chaps like David Whitaker and John Peel, even Terry Nation's stories got done.
Target Books were the main publisher of Doctor Who books from the 70's to the 90's, novelising all the TV stories for fans to take home in the days before VHS players and internet. To this day they come in pretty handy for missing episodes.
Target actually outlasted Classic Who by a few years but with no more stories to novelise, they eventually died. Before doing so they did novelise a few odds and ends like Doctor Who and the Pescatons and some Lost Season stories.
Reminder that books Edit
There's about a billion of these things and a ton of authors involved (even cast members like Ian Marter and producers like Williams and Hinchcliffe got in on the action) but most of them seem to be written by Terrance Dicks.
- Occasionally they would change the title of a TV story for the novelisation, eg. Spearhead From Space was renamed Doctor Who and the Auton Invasion for the novel. Because fuck you, that's why.
- Some enterprising fans in New Zealand filled in the gaps in the series by writing the books themselves.
- The VNA's more or less pick up where they left off, albeit with original, "more mature" stories.
- We will likely never get novelizations of the New Series episodes, because why would anyone read a book of something they can watch in forty minutes?