Challenging the often-hyperbolic claims that have been made around the use of data in election campaigns for voter manipulation and suppression, this book provides unrivalled evidence of how parties actually behave. It shows that data-driven campaigning practice is not inherently problematic or new, but neither is it uniform, rather systemic, regulatory and party level factors affecting the nature of campaigning. Providing detailed empirical examples from Australia, Canada, Germany, the UK and US, this book shows how parties campaign and explains why parties differ, thereby resetting prevailing understanding of the role of data in campaigns.