Premise: Comet in Moominland (Swedish: "Kometjakten" / "Mumintrollet på kometjakt" / "Kometen kommer") is the second in Tove Jansson's series of Moomin books. Published in 1946, it marks the first appearance of several main characters, like Snufkin and the Snork Maiden.
Hypothesis: Readers of Tove Jansson's series didn't know about Snufkin and the Snork Maiden before Comet in Moominland got published.