The concept of “characters” lies at the heart of many central issues in evolutionary biology. Characters distinguish taxa, cause fitness differences, and generally are the fundamental units of comparison for studies of phenotypic evolution. Historically, the concept of characters originated in morphology and comparative anatomy, where it was intimately connected to the issue of homology. The summer school is mainly aimed at early-stage (PhD or postdoc) empirical and theoretical researchers with a general background and/or interest in developmental and/or evolutionary biology. More senior investigators are welcome to apply as well. Exceptions can be made for motivated masters students. Participants of previous Venice Summer Schools in Evo-Devo are expressly encouraged to reapply as this course has an entirely different topic than previous editions. The course will equip participants with the conceptual tools to engage in a productive discussion of the notion of “characters,” and to relate this notion to their own research questions and explanations.