This Festschrift is dedicated to Erzsébet Csuhaj-Varjú in recognition of her contributions to theoretical computer science. Over the course of her distinguished career, she has played a pivotal role in advancing the fields of formal languages, automata theory, and bioinspired computation. Her work as a research collaborator, mentor, and organizer has been instrumental in fostering a vibrant community, these successes are reflected in the papers contributed to this volume.  Prof. Csuhaj-Varjú graduated with a master’s degree in mathematics from the Kossuth Lajos University in Debrecen in 1977, she received her PhD in 1993, became a doctor of the Hungarian Academy of Sciences in 2003, and habilitated in computer science from Eötvös Loránd University. From 1979 to 2011 she was a researcher and manager at the Computer and Automation Research Institute of the Hungarian Academy of Sciences, she became a full professor at Eötvös Loránd University in 2008. Prof. Csuhaj-Varjú initiated research directions in the theory and applications of formal languages and automata, unconventional computation, and distributed systems, and played a decisive role in the development of the theory of grammar systems.