A "Black Swan" is an improbable event that has a major impact, and happens when people least expect it (e.g.: 9/11, WWI, 2008 economy crisis).
Black swans can have a negative or positive impact. The negative ones can wipe out things build over decades in a matter of seconds, while the positive ones can take longer (e.g.: the advancement of technology in the past 30 years). The positive ones need to be put on scale with longer intervals of time. They’re harder to notice if you look at a specific time in history.
- Nytimes 10 Best Books of 2020 is at https://www.nytimes.com/2020/11/23/books/review/best-books.h.... Their larger list of 100 Notable Books of 2020 is at https://www.nytimes.com/interactive/2020/books/notable-books...
- The Nytimes’ critics have their own list at https://www.nytimes.com/2020/12/02/books/times-critics-top-b...
- Time’s 100 Must-Read Books of 2020 is at https://time.com/collection/must-read-books-2020/
- Time’s lists of The 10 Best Nonfiction Books of 2020 is at https://time.com/5913865/best-nonfiction-books-2020/ and The 10 Best Fiction Books of 2020 is at https://time.com/5913197/best-fiction-books-2020/
- The Guardian breaks down their list of the Best Books of 2020 into several categories. Link: https://www.theguardian.com/books/2020/nov/28/best-books-of-...
- The year-end lists on Goodreads, Best Books of 2020 at https://www.goodreads.com/choiceawards/best-books-2020, Most Popular Books Published In 2020 at https://www.goodreads.com/book/popular_by_date/2020, typically cast a wider net on what a broader audience is reading.