This issue contains the last articles dedicated in memory of Stephan Ruscheweyh, the founding editor of . We are grateful for the overwhelming response to the call for articles—they filled a double issue, and include four articles in this issue. They are a fitting tribute to the vision and dedication of Stephan Ruscheweyh. The editorial board thanks Vladimir Andrievskii, Filippo Bracci, and Elias Wegert for all their work in editing and managing the special issues.