We use this chapter to do three things: (1) discuss the various data and measures – some existing and some new – that we will use throughout the book; (2) identify how apportionment of Southern delegates was determined, discuss how Southern delegation size varied over time, and explain why the South was able to maintain a significant presence at GOP conventions while not providing any electoral votes for generations; and (3) explain why focusing on factional GOP politics in the late nineteenth- and early twentieth-century South matters for understanding the emergence of the Republican Party as an electoral force in the late twentieth-century South, through an innovative multivariate analysis of “whiteness politics.”