This chapter describes the process of reverse transcription and how to select a kit for the process, as well as a discussion on cDNA dilutions. The polymerase chain reaction (PCR) is described in detail, along with instructions for designing primers. This chapter is mostly a discussion on how PCR works and what is necessary for a good reaction, because the majority of PCR experiments have steps that depend entirely on which polymerase is being used in the experiment. There is a section on the workings and considerations involved in quantitative PCR, as well as quantitative PCR data analysis. This chapter ends with a troubleshooting section as well as a section on proper PCR controls.