This chapter presents an outline of how advertisements work and a brief history of the development of political advertising from print to the internet. Political advertising, was pioneered in the US and has reached its highest level of sophistication there. It also provides an account of the various approaches adopted in both the US and Britain since the Second World War, up to and including the Brexit vote in the UK and the 2016 US presidential election. The chapter discusses the new digitised forms of political communication on public relations. It notes that the rise of the internet has substantially expanded the range of alternatives to traditional print and TV advertising available to political actors. A striking feature of the digital era of political communication is the capacity of citizen-voters to subvert official campaign messages with 'mash ups' and other forms of digitally altered image.