This issue introduces some new developments in the journal’s editorial structure. Most significant of these is that Charles Taylor has decided to step down as Editor in order to concentrate on some new professional commitments. Chuck has been a prominent member of the artificial life community ever since he participated in Chris Langton’s first Artificial Life workshop at Los Alamos in 1987. He helped Chris create this journal as a founding Associate Editor, and in the middle of volume 3 he joined Chris as one of the journal’s editors. Chuck’s sound and thoughtful judgment, his decisive action, and his vision for future opportunities provided the consistent creative energy that helped the journal to grow into a mature scientific periodical over the next four years. Not least among his important contributions were his pioneering efforts to create a professional organization that would provide a stable, democratic, and genuinely international foundation for the journal’s future. I know that journal’s readers will want to join me in thanking Chuck for his years of service as our Editor, and I want to express my personal appreciation for the opportunity to work alongside him as Co-Editors-inChief for the past year. The journal’s editorial structure will continue to evolve for a while as the International Society for Artificial Life grows into its new role as the journal’s governing body. Some of these changes also occur in this issue. David Stork is stepping down as the journal’s Book and Software Review Editor, and I want to warmly thank him for filling this role admirably right from the journal’s inception. I am pleased to announce that those responsibilities will now be shouldered by Inman Harvey of Sussex University, who has been an active and influential member of the artificial life community for many years. Readers are invited to suggest books that we might review to Inman by email (inmanh@cogs.susx.ac.uk). I am also pleased to announce that Philip Husbands, also of Sussex University, has agreed to join the journal’s Editorial Board, thus further strengthening the journal’s representation in Europe and its expertise in both theoretical and applied aspects of genetic algorithms and evolutionary robotics. The articles and reports published in this issue nicely reflect the interdisciplinary breadth of contemporary artificial life. In “Mutualism promotes diversity and stability in a simple artificial ecosystem” Elizaveta Pachepsky, Tim Taylor, and Stephen Jones address how ecological interactions among organisms affect the dynamics of a spatially explicit agent-based artificial ecosystem. While theoretical ecologists have given the issue of ecosystem stability much insightful analysis over the past generation (e.g., [4]), the primary aim of Pachepsky et al. is complementary: to understand how evolutionary dynamics can sometimes introduce drives for ongoing evolution rather than stasis. The artificial life community has increasingly included efforts to apply agent-based evolutionary algorithms to a variety of issues concerning the self-organization and evolution of social and cultural systems. An illustration from linguistics is Henry Brighton’s paper in this issue, “Compositional syntax from cultural transmission.” Traditional explanations of the origin and structure of language appeal to the biological evolution of an innate language acquisition device. But this does not account for how language as a cultural phenomenon can evolve in the absence of biological evolution. Brighton argues that compositional structure—one of the syntactic hallmarks of human language—can be explained by the dynamics of cultural evolution. This work