This introductory chapter explores the foundations of agile marketing and its relevance to B2B startups. By reviewing the academic literature, it outlines the principles of agile methodologies, tracing their origins from software development to marketing applications. The chapter highlights how agility enables startups to face the challenges related to more and more competitive markets, such as long sales cycles, limited resources and complex decision-making processes. By focusing on flexibility and iterative testing, agile marketing helps new ventures to grow in dynamic environments. In fact, the role of agile marketing strategies is key for firms to adapt to market uncertainties and technological advancements.