We assemble a novel dataset in order to test theoretical propositions we develop on how states intervene in the elections of others. We start off with a random or representative sample of about 10 per cent of all elections since the end of World War II. Each of these is a case for us. We add a set of potential interveners, powers and organizations that may have a stake in intervening. We scour primary and secondary sources to extract information on how the government and opposition in the target state view relations with the potential interveners. We also extract information on whether and how the intervener acted in support of processes, or of candidates. This chapter is a codebook of how we constructed these novel, theory relevant variables. In addition, we supply extensive case-study notes. In those notes, we connect each of our coding decision to specific strings of text in the sources we used. The resulting database allows us to test the key propositions we develop.