Designing the optimal electoral system for a country requires careful consideration, particularly when the electorate and/or the electoral system are subject to manipulation. Elections are a form of political participation and act as a periodic barometer of public opinion. They provide legitimacy and stability for political decisions, with equal, direct, secret and free suffrage being standard principles of democratic elections. However, the specifics of these principles, such as the voting age or residency and citizenship requirements, vary from country to country and can be defined individually when drafting a constitution. In addition to electoral principles, this chapter presents different electoral systems. The main groups are plurality, majoritarian, proportional, mixed, and hybrid systems. Some countries apply the ‘winner takes all’ principle, and more than one majority may be required to win elections. There are numerous variants and their intricacies, such as the ‘first past the post’ system; the ‘block vote’ system; the importance of party lists through ‘party block vote’; ranking through ‘alternative vote’; and the ‘two-round system’ if a candidate or party does not directly reach a certain quorum. Ultimately, the question arises: Which electoral system is optimal for which state? What are the decisive factors? What are the advantages and disadvantages of each system? This chapter helps to untangle the enigma of electoral designs, includes a visualisation chart and offers solutions to one of the most fundamental elements of a constitutional state.