This theme focuses on approaches to visualizing phylogenies - evolutionary trees showing lineages of descent of individuals, populations or species from their hypothesized common ancestors. The only figure in 'On the Origin of Species' (Darwin, 1859) is a phylogenetic tree visualized in a manner we would consider to be 'modern' - attempting to represent a model of the evolutionary process. This is in contrast to the very literal tree visualizations by Haeckel at the same time showing a gnarled trunk leading to humans at the apex and numerous side-branches leading to other, presumably lesser, species. Modern phylogenetic trees try to represent numerous data dimensions (relatedness, time, genetic divergence, trait evolution, geographical distribution and statistical support) often in a single figure with varying degrees of success. The aim of this theme is to explore how best to represent complex multi-dimensional evolutionary information on a phylogenetic tree in order to convey clear and simple interpretations.