Noon Universe

The Noon Universe (Russian term: "Мир Полудня" or "Мир Полдня" – "World of Noon"; also known as the “Wanderers’ Universe”) is a fictional future setting for a number of hard science fiction novels written by Arkady and Boris Strugatsky. The universe is named after ''Noon: 22nd Century'', chronologically the first novel from the series and referring to humanity reaching its noon in the 22nd century.

According to Arkady Strugatsky, the brothers at first did not make a conscious effort to create a fictional universe. Rather, they reused characters and settings from prior works whenever they found it convenient. It was only later that they began drawing on common themes and plot threads from various novels to create newer works. Provided by Wikipedia