Hey there kiddo! So, you know how when you draw something, you can make it look however you want? Well, adults were doing that too, but with writing instead of pictures!
In Poland, a long time ago, there was a special way that writers were told to write called socialist realism. This was because the government wanted people to only talk about certain things in their writing, like how great communism was and how much they should love the government.
It was kind of like when your teacher tells you what to write about for a school assignment. The government was like the teacher and the writers had to write about what they wanted, but only if it was the right subject. They had to make sure everything they wrote sounded like it was totally okay with the government.
This meant that the stories that people wrote were often not very fun or exciting because they had to follow all the rules. They couldn't just write whatever they wanted, like a story about unicorns or superheroes.
So, socialist realism in Polish literature meant that writers had to write stories that the government liked, even if they didn't want to. It was like being told what to draw, but with words instead of pictures.