The figure is Charles Darwin's first drawing of an evolutionary tree from his first notebook on transmutation of species (1837) on view at the Museum of Natural History in Manhattan. Darwin's revolutionary idea was that there is a tree describing the evolutionary relationships of all existing life on earth. Mathematical and statistical research in the area includes studying the properties of the mathematical methods for reconstructing the tree from data such as DNA sequence data and developing and exploring statistical methods for incorporating the tree into the analysis of trait data from the existing species at the tips of the tree.- *Elizabeth Housworth*