Originally written in 1956, the book was made into an animated movie by Disney in 1961 and a live-action one in 1996. Disney has produced a whole bunch of sequels to their 101 Dalmatians movies, but none of them were based on the original author's actual novel sequel: The Starlight Barking. Why? Because it's an insane acid trip that slowly mutates into a David Bowie rock opera with an alien dog messiah in it.
The Little-Known Sequel That Ruins It:
Smith's sequel picks up where the first book left off, with the titular 101 Dalmatians now grown and living on their Dalmatian plantation. And then things get weird. They wake up one morning to discover that every non-dog on Earth has fallen asleep. This includes their former nemesis, Cruella de Vil, who is featured only in a tiny cameo. Reasonably weirded out, the dogs also realize that they are telepathic and no longer need to eat. Also they can fly. Everybody can fly now. And they can open doors with their minds, because why not. The last time someone sat down to write this particular brand of crazy stream-of-consciousness story, the Church of Scientology was founded.