CiE 2021 is the seventeenth conference organized by the Association Computability in Europe. The Computability in Europe conference (CiE) series has built up a strong tradition for developing a scientific program which is interdisciplinary at its core bringing together all aspects of computability and foundations of computer science, as well as the interplay of these theoretical areas with practical issues in CS and other disciplines such as biology, mathematics, history, philosophy, and physics.