This chapter covers the concept of phylogenetics and gives a basic overview of how to read cladograms. The chapter starts out with an introduction to taxonomic classification and the rules for expressing scientific names, a concept that is helpful when discussing dinosaurs. The bulk of the chapter is used to describe how phylogenetics are used to discern evolutionary relationships between organisms. Concepts like ancestral versus derived traits are introduced while demonstrating how one uses these characters to construct cladograms and use them to properly interpret relationships between organisms. The chapter ends by discussing some of the uncertainties that come along with using phylogenetic methods.