This volume is a "Festschrift" in honor of Leif Tibell on the occasion of his 60th birthday on 16 November 2004. Leif has been a member of the staff at the Department of Systematic Botany, Uppsala University, for his entire professional career. It is therefore appropriate to present him with a volume of Symbolae Botanicae Upsalienses, a serie published by the Department. The volume contains a considerable number of contributions by former students, friends and colleagues in different parts of the world. It is mainly focused on lichen taxonomy and biogeography, but also other aspects of lichenology that are relevant to Leif's own work are represented.