This special issue of Artificial Life journal presents some of the best papers of the Conference on Artificial Life ALIFE 2021, which was originally scheduled to be held in Prague, Czech Republic, on July 19-23. However, because of the COVID-19 pandemic and its repercussions, the ALIFE 2021 conference took place solely online (Figure 1). Nevertheless, it was a wonderful event with around 400 participants and a busy program that offered 9 keynote talks, 27 hours of 6 special sessions, almost 40 hours of 11 workshops, 5 tutorials, and 64 talks in parallel sessions. The organizing committee worked intensively to create a virtual conference that gave as much of a real conference atmosphere as possible, so there were also a virtual art gallery, virtual pubs, and virtual coffee rooms. The social program offered the documentary movie Solutions and a THEaiTRE project Can a Robot Write a Theatre Play? The program also included a dedicated session 1971-2021: Fifty Years with Autopoiesis, in memory of Francisco Varela and Humberto Maturana, who passed away that year.The theme of ALIFE 2021 was Robots: The century past and the century ahead, on the occasion of the centenary of Karel Čapek's R.U.R. (subtitled as Rossum's Universal Robots; Čapek, 1920) and the worldwide-used word robot, which comes from this play, which premiered in Prague in 1921 ( Čejková, 2021). In honor of this famous literary work, we had a student essay competition where undergraduate and PhD students submitted essays related to R.U.R., robots, artificial life, and/or artificial intelligence. Another literary piece of work that paid tribute to R.U.R. was the book Robot 100 ( Čejková, 2020). The Czech edition was released in November 2020 by the University of Chemistry and Technology Prague (which hosted the ALIFE 2021 conference) and included contemporary perspectives on Čapek's one-hundred-year old piece through the eyes of one hundred personalities from the Czech Republic and from around the world, including scientists, writers, journalists,