This issue of is devoted to the memory of Frederick W. Gehring, who has served as a distinguished member of the Editorial Board. He has left his imprint on this journal, having inspired a number of its articles. Surely his outstanding contributions to mathematical analysis and his selfless service to the mathematical community will be long remembered.

We are grateful to the Special Issue Editors Kari Hag, Gaven Martin, Olli Martio, Bruce Palka and Matti Vuorinen for their dedication and enthusiasm to successfully complete this project.

S. Ruscheweyh and E. B. Saff

Editors-in-Chief,