This chapter provides a basic introduction to the analysis of population genetic data based on previously published data. Please note that this is not a primer on population genetics; a basic understanding of molecular tools and population genetics is required to follow these exercises. The methods covered in this chapter can be applied to typical molecular marker data including dominant marker systems (such as random amplified polymorphic DNA [RAPD], restriction fragment length polymorphism [RFLP], amplified restriction length polymorphism [AFLP], and related variations) and codominant marker systems (including isozymes, microsatellites, also known as simple sequence repeats [SSR], and single nucleotide polymorphisms [SNP]). The exercises apply to either codominant (typically SSR or SNP) or dominant marker systems (typically RAPD, RFLP, and AFLP) for haploid or diploid species but do not necessarily apply to sequence-based data, which uses different approaches that are beyond the scope of this chapter.